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Effects of Low-Level Laser Therapy (LLLT) on the Nuclear Factor (NF)-kB Signaling Pathway in Traumatized Muscle
Abstract
To investigate the effects of low-level laser therapy (LLLT) on nuclear factor kappa B (NF-kappaB) activation and inducible nitric oxide synthase (iNOS) expression in an experimental model of muscle trauma.
Injury to the gastrocnemius muscle in the rat was produced by a single impact blunt trauma. A low-level galium arsenide (Ga-As) laser (904 nm, 45 mW, and 5 J/cm2) was applied for 35 seconds duration, continuously.
Histological abnormalities with increase in collagen concentration, and oxidative stress were observed after trauma. This was accompanied by activation of NF-kappaB and upregulation of iNOS expression, whereas protein concentration of I kappa B alpha decreased. These effects were blocked by LLLT.
LLLT reduced the inflammatory response induced by trauma and was able to block the effects of reactive oxygen species (ROS) release and the activation of NF-kappaB. The associated reduction of iNOS overexpression and collagen production suggest that the NF-kappaB pathway may be a signaling route involved in the pathogenesis of muscle trauma.
... Third, it was shown that early laser treatment after structural muscle trauma can reduce the formation of scar tissue [43]. After structural gastrocnemius muscle injury in a rat model, early treatment with a CW laser (wavelength, 904 nm; PW laser mode; pulse length and peak power not mentioned; average power, 45 mW) reduced the inflammatory response [43]. ...
... Third, it was shown that early laser treatment after structural muscle trauma can reduce the formation of scar tissue [43]. After structural gastrocnemius muscle injury in a rat model, early treatment with a CW laser (wavelength, 904 nm; PW laser mode; pulse length and peak power not mentioned; average power, 45 mW) reduced the inflammatory response [43]. Additionally, the laser treatment blocked the activation of the transcription factor nuclear factor kappa B (NF-κB) and the effects of reactive oxygen species release [43]. ...
... After structural gastrocnemius muscle injury in a rat model, early treatment with a CW laser (wavelength, 904 nm; PW laser mode; pulse length and peak power not mentioned; average power, 45 mW) reduced the inflammatory response [43]. Additionally, the laser treatment blocked the activation of the transcription factor nuclear factor kappa B (NF-κB) and the effects of reactive oxygen species release [43]. NF-κB is active in many inflammatory diseases, including atherosclerosis and others [44], and anti-inflammatory activity has been linked to a suppression of NF-κB activation [45]. ...
The choice of parameters for laser beams used in the treatment of musculoskeletal diseases is of great importance. First, to reach high penetration depths into biological tissue and, secondly, to achieve the required effects on a molecular level. The penetration depth depends on the wavelength since there are multiple light-absorbing and scattering molecules in tissue with different absorption spectra. The present study is the first comparing the penetration depth of 1064 nm laser light with light of a smaller wavelength (905 nm) using high-fidelity laser measurement technology. Penetration depths in two types of tissue ex vivo (porcine skin and bovine muscle) were investigated. The transmittance of 1064 nm light through both tissue types was consistently higher than of 905 nm light. The largest differences (up to 5.9%) were seen in the upper 10 mm of tissue, while the difference vanished with increasing tissue thickness. Overall, the differences in penetration depth were comparably small. These results may be of relevance in the selection of a certain wavelength in the treatment of musculoskeletal diseases with laser therapy.
... Third, it was shown that early laser treatment after structural muscle trauma can reduce the formation of scar tissue [41]. In a rat model of structural gastrocnemius muscle injury, the early treatment with a CW laser (wavelength, 904 nm; PW laser mode; pulse length and peak power not mentioned; average power, 45 mW) reduced the inflammatory response [41]. ...
... Third, it was shown that early laser treatment after structural muscle trauma can reduce the formation of scar tissue [41]. In a rat model of structural gastrocnemius muscle injury, the early treatment with a CW laser (wavelength, 904 nm; PW laser mode; pulse length and peak power not mentioned; average power, 45 mW) reduced the inflammatory response [41]. Additionally, the laser treatment was able to block the effects of reactive oxygen species release and the activation of the transcription factor nuclear factor kappa B (NF-κB) [41]. ...
... In a rat model of structural gastrocnemius muscle injury, the early treatment with a CW laser (wavelength, 904 nm; PW laser mode; pulse length and peak power not mentioned; average power, 45 mW) reduced the inflammatory response [41]. Additionally, the laser treatment was able to block the effects of reactive oxygen species release and the activation of the transcription factor nuclear factor kappa B (NF-κB) [41]. NF-κB is found to be active in many inflammatory diseases including atherosclerosis and others [42], and a suppression of NF-κB activation has been linked to antiinflammatory activity [43]. ...
The choice of parameters for laser beams used in the treatment of musculoskeletal diseases is of great importance. First, to reach high penetration depths into biological tissue and, secondly, to achieve the required effects on a molecular level. The penetration depth depends on the wavelength since there are multiple light-absorbing and scattering molecules in tissue with different absorption spectra. The present study is the first comparing the penetration depth of 1064 nm laser light with light of a smaller wavelength (905 nm) using high-fidelity laser measurement technology. Penetration depths in two types of tissue (porcine skin and bovine muscle) were investigated. The transmittance of 1064 nm light through both tissue types was consistently higher than of 905 nm light. The largest differences (up to 5.9%) were seen in the upper 10 mm of tissue, while the difference vanished with increasing tissue thickness. The higher penetration was most likely due to a combination of lower absorption in hemoglobin and less scattering at larger wavelengths, and not due to absorption in melanin. Overall, differences in penetration depth were comparably small and high peak power and short pulse lengths of laser light seem to be more important to efficiently treat deep musculoskeletal diseases.
... Low-level light therapy (LLLT), or photobiomodulation (PBM), utilizes low-intensity red and near-infrared (NIR) light from specialized lasers or light-emitting diodes to treat a variety of human conditions (1). Multiple experimental and clinical studies on light treatment with red/NIR irradiation ranging from 600 to 1100 nm showed promising results for muscle recovery (2,3), wound healing (4,5), reduction of inflammation (1,6), pain (7), as well as neurotrauma and neurodegenerative diseases (8,9). In case of PBM, red/NIR light is absorbed by cytochrome c oxidase (CCO), resulting in the activation of mitochondria and the subsequent generation of reactive oxygen species (ROS) through a chain of reactions (10,11). ...
... Light power density was adjusted to be 0.1 W cm À2 and the light irradiation time was in 1 s -5 min interval (1 min of irradiation is equivalent to a dose of 6 J cm À2 , so the maximum irradiation dose was 30 J cm À2 ). These light power density and doses were chosen because red/NIR light with such parameters was shown to provide positive effects on cells and tissues, while not causing cell phototoxicity (1)(2)(3)(4)(5)(6)(7)(8)(31)(32)(33)(34)(35)(36). ...
... dose (J/cm )2 Light irradiation dose (J/cm ) Amendment of the cytokine profile in macrophages following 650 and 808 nm light application. Graphs show the light-induced changes of pro-inflammatory cytokines IL-1, IL-6, TNF-a and anti-inflammatory cytokines IL-10, TNF-b in nonactivated and zymosan-activated macrophages. ...
Low-level light therapy (LLLT) is emerging as a promising therapeutic approach to modulate the biochemical and molecular processes within living cells. LLLT is known to produce local and systemic effects; therefore, immune cells in local tissues or in the circulation are affected by light. However, this specific effect remains weakly explored. In this study, the effect of red (650 nm) and NIR (808 nm) light on phagocytosis (respiratory burst), cytokine expression, mitochondrial activity, ROS generation, Ca²⁺ influx and membrane depolarization in macrophages in vitro is investigated. Both the phagocytic capacity and adhesion of macrophages strongly (~2.5 times) increased in the first hours after exposure to light in a dose-dependent manner. The light-evoked upregulation of phagocytosis is found to be less efficient than the maximal pharmacologically induced enhancement of ~3.2 times. Also, red/NIR light reduces the production of pro-inflammatory cytokines and activates the secretion of anti-inflammatory cytokines by several times in activated macrophages. At the same time, the viability shows a biphasic dose response: it increases after irradiation with lower doses (0.3-1 J/cm²) and decreases after treatment with higher doses (18-30 J/cm²), which is apparently associated with the upregulation of ROS generation, followed by an increase in the mitochondrial activity.
... PBM exhibits anti-inflammatory and growth stimulation properties, making it eligible as an intervention for the treatment of OM. Laser energy is known to be absorbed by chromophores in the respiratory chain, leading to upregulated ATP production, resulting in accelerated tissue repair [31][32][33]. Though the biological mechanisms contributing to the therapeutic benefits of PBM have not been completely understood yet, current evidence from clinical studies indicates that PBM significantly diminishes clinical inflammation and prevents fibrosis [31][32][33]. ...
... Laser energy is known to be absorbed by chromophores in the respiratory chain, leading to upregulated ATP production, resulting in accelerated tissue repair [31][32][33]. Though the biological mechanisms contributing to the therapeutic benefits of PBM have not been completely understood yet, current evidence from clinical studies indicates that PBM significantly diminishes clinical inflammation and prevents fibrosis [31][32][33]. The effect of LLT on the tissues has been shown to depend on the irradiation parameters, including wavelength density as well as exposure time, cell type and oxidation status [6,[34][35][36][37]. ...
... The power of the laser used ranged between 50 and 500 mW, and the energy density ranged from 4 to 6.5 J/cm 2 . Optimal irradiation and dose parameters are likely to vary according to the severity of the underlying pathology, cellular layers affected in the mucosa as well as other patient-associated factors [32,33]. Pathobiological mechanisms of cellular damage manifested as disruptions of tight junctions and matrix metalloproteinase-mediated connective tissue impairment may be a common factor amongst chemotherapeutic regimens. ...
Oral mucositis is a debilitating complication of chemotherapy, characterized by erythema, ulcers and oedema of the oral mucosa. This review aimed to evaluate the efficacy of Photobiomodulation in the treatment of oral mucositis using meta-analysis and trial sequential analysis, and also to assess the quality of the results by Grading of Recommendations, Assessment, Development and Evaluation (GRADE). A comprehensive search of three databases, including Embase, Medline and Central, was performed to identify randomized controlled trials studying the efficacy of Photobiomodulation in the treatment of cancer chemotherapy-induced oral mucositis. The primary outcome was reduction in the severity of oral mucositis. Secondary outcomes were pain relief, duration of oral mucositis and adverse effects. The meta-analysis was performed using the random-effects model, and random errors of the meta-analyses were detected by trial sequential analysis. A total of 6 randomized controlled trials with 398 participants were included in our analysis. Photobiomodulation significantly reduced the severity of oral mucositis when compared to sham radiation (RR 0.43, 95% CI 0.20 to 0.93; p < 0.05). Sensitivity analysis by excluding trials with high risk of bias reiterated the robustness of our results (RR 0.28, 95% CI 0.16 to 0.48). Trial sequential analysis illustrated that the evidence from the meta-analysis was conclusive. The result of the meta-analyses with trial sequential analysis illustrated that Photobiomodulation is an effective therapeutic intervention for the treatment of oral mucositis, and the evidence gathered can be considered conclusive with a moderate level of certainty according to GRADE. Further trials are recommended to standardize the laser parameters required for the optimal effect.
... The presumptive mechanism of action of t-PBM involves the absorption of photons by chromophores in the mitochondria, specifically cytochrome c oxidase (CCO), which is a component of the mitochondrial respiratory chain (Oron et al., 2007). Research has suggested that the above-mentioned mechanisms of t-PBM may impact the pathophysiology of neuropsychiatric disorders via (1) modulation of oxidative stress (de Freitas & Hamblin, 2016;Molendijk et al., 2014;Rizzi et al., 2006); (2) downregulation of immune cell alterations and the NLRP3 inflammasome complex (Choi et al., 2012;de Barros Silva et al., 2022;de Brito et al., 2022;Guo et al., 2021;Li, Liang, et al., 2020;Ryu et al., 2022;Wu et al., 2022); (3) reduction of proinflammatory cytokines levels such as TNFα, CRP, IL-1β, and IL-6 (De Marchi et al., 2021;Esteves et al., 2022;Lima et al., 2014;Lu et al., 2017;Shaikh-Kader et al., 2021;Zheng et al., 2021); (4) deactivation of neurotoxic microglia (Choi et al., 2012;Ketz et al., 2017;Lu et al., 2017;Tao et al., 2021;Wang et al., 2021), and (5) increase of BDNF gene expression (Heo et al., 2019;Yan et al., 2017). ...
... In addition to the effects on CCO, t-PBM can activate light-sensitive ion channels, such as transient receptor potential channels, allowing calcium (Ca 2+ ) to enter the cell(de Freitas & Hamblin, 2016;Sharma et al., 2023). This phenomenon can activate downstream signaling pathways via reactive oxygen species (ROS), cyclic adenosine monophosphate (cAMP), NO, and Ca 2+ (de Freitas & Hamblin, 2016).These pathways can enhance transcription factors, such as the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), cyclic AMP-responsive element-binding protein (CREB), and activator protein-1 (AP-1)(Bathini et al., 2022;Rizzi et al., 2006). t-PBM's impact on cellular processes includes protein synthesis, cell migration and proliferation, and modulation of anti-inflammatory responses(de Freitas & Hamblin, 2016;Dompe et al., 2020). ...
Obsessive-compulsive disorder (OCD) is a disabling neuropsychiatric disorder that affects about 2%-3% of the global population. Despite the availability of several treatments , many patients with OCD do not respond adequately, highlighting the need for new therapeutic approaches. Recent studies have associated various inflammatory processes with the pathogenesis of OCD, including alterations in peripheral immune cells, alterations in cytokine levels, and neuroinflammation. These findings suggest that inflammation could be a promising target for intervention. Transcranial photobio-modulation (t-PBM) with near-infrared light is a noninvasive neuromodulation technique that has shown potential for several neuropsychiatric disorders. However, its efficacy in OCD remains to be fully explored. This study aimed to review the literature on inflammation in OCD, detailing associations with T-cell populations, monocytes, NLRP3 inflammasome components, microglial activation, and elevated proinflamma-tory cytokines such as TNF-α, CRP, IL-1β, and IL-6. We also examined the hypothesis-based potential of t-PBM in targeting these inflammatory pathways of OCD, focusing on mechanisms such as modulation of oxidative stress, regulation of immune cell function, reduction of proinflammatory cytokine levels, deactivation of neurotoxic microglia, and upregulation of BDNF gene expression. Our review suggests that t-PBM could be a promising, noninvasive intervention for OCD, with the potential to modulate underlying inflammatory processes. Future research should focus on rand-omized clinical trials to assess t-PBM's efficacy and optimal treatment parameters in OCD. Biomarker analyses and neuroimaging studies will be important in understanding the relationship between inflammatory modulation and OCD symptom improvement following t-PBM sessions.
... LLLT also suppresses inflammatory responses and oxidative activity and at the same time stimulates antioxidant activity [201]. It was revealed that the synthesis of nuclear factor kappa B (NF-κB), the key inflammatory transcription factor was inhibited [202]. LLLT also reduces OS by inhibiting the production of ROS and inducible forms of NOS expression in oxidatively-stressed cells [202,203]. ...
... It was revealed that the synthesis of nuclear factor kappa B (NF-κB), the key inflammatory transcription factor was inhibited [202]. LLLT also reduces OS by inhibiting the production of ROS and inducible forms of NOS expression in oxidatively-stressed cells [202,203]. It is well-recognized that NO contributes to the majority of neurodegenerative illnesses such as MS [204]. ...
This narrative review summerizes the mitochondria dyafunction related to neurodegenerative disorders and summerizes the different treatment methods of them
... 26,27 It was revealed that laser radiation inhibited nuclear factor kappa B (NF-κB), the key inflammatory transcription factor, and the related signaling pathways like inflammatory cytokines. 28,29 LLLT also reduced oxidative stress by inhibiting the production of reactive oxygen species (ROS) and inducible form of nitric oxide synthase (iNOS) expression in oxidatively-stressed cells. 24,[29][30][31] Moreover, low-level laser radiation enhanced the production and release of various small molecules and growth factors, including TGF-β, brain-derived neurotrophic factor (BDNF), platelet-derived growth factor, and glial-derived neurotrophic factor. ...
... 28,29 LLLT also reduced oxidative stress by inhibiting the production of reactive oxygen species (ROS) and inducible form of nitric oxide synthase (iNOS) expression in oxidatively-stressed cells. 24,[29][30][31] Moreover, low-level laser radiation enhanced the production and release of various small molecules and growth factors, including TGF-β, brain-derived neurotrophic factor (BDNF), platelet-derived growth factor, and glial-derived neurotrophic factor. [32][33][34] In regenerative medicine, besides the secretion of the growth factors, inhibiting the inflammatory microenvironment is crucial. ...
Introduction: Multiple sclerosis (MS) is an autoimmune disease. Inflammatory cells, cytokines, and chemokines play a major role in the pathogenesis of the disease. Low-level laser therapy (LLLT) as a photobiostimulation approach could affect a wide range of cellular responses. LLLT inhibits the inflammatory signaling pathway, improves cell viability, inhibits apoptosis, modulates immune responses, and induces the production of growth factors.
Methods: In this review, we discuss the effect of LLLT on cellular responses and its application in the treatment of MS. Such keywords as “low-level laser therapy”, “photobiomodulation” and “multiple sclerosis” were used to find studies related to laser therapy in MS in Google scholar, PubMed, and Medline databases.
Results: LLLT reduced the inflammatory immune cells and mediators. It also enhanced the regeneration of neurons.
Conclusion: Investigations showed that besides current treatment strategies, LLLT could be a promising therapeutic approach for the treatment of MS.
... During a previous study (Kudsi et al. 2020), we established a non-invasive blunt injury model using a custom device based on an approach described by Rizzi et al. (2006) and by Dos Santos Haupenthal et al. (2020), which has been widely used in other research projects (Dos Santos Haupenthal et al. 2020;Rizzi et al. 2006). This study confirmed that this approach caused substantial muscle injury without puncturing the skin or fracturing hindlimb bones. ...
... During a previous study (Kudsi et al. 2020), we established a non-invasive blunt injury model using a custom device based on an approach described by Rizzi et al. (2006) and by Dos Santos Haupenthal et al. (2020), which has been widely used in other research projects (Dos Santos Haupenthal et al. 2020;Rizzi et al. 2006). This study confirmed that this approach caused substantial muscle injury without puncturing the skin or fracturing hindlimb bones. ...
Musculoskeletal pain is a widely experienced public healthcare issue, especially after traumatic muscle injury. Besides, it is a common cause of disability, but this pain remains poorly managed. However, the pathophysiology of traumatic muscle injury-associated pain and inflammation has not been fully elucidated. In this regard, the transient receptor potential ankyrin 1 (TRPA1) has been studied in inflammatory and painful conditions. Thus, this study aimed to evaluate the antinociceptive and anti-inflammatory effect of the topical application of a TRPA1 antagonist in a model of traumatic muscle injury in rats. The mechanical trauma model was developed by a single blunt trauma impact on the right gastrocnemius muscle of Wistar male rats (250–350 g). The animals were divided into four groups (Sham/Vehicle; Sham/HC-030031 0.05%; Injury/Vehicle, and Injury/HC-030031 0.05%) and topically treated with a Lanette® N cream base containing a TRPA1 antagonist (HC-030031, 0.05%; 200 mg/muscle) or vehicle (Lanette® N cream base; 200 mg/muscle), which was applied at 2, 6, 12, 24, and 46 h after muscle injury. Furthermore, we evaluated the contribution of the TRPA1 channel on nociceptive, inflammatory, and oxidative parameters. The topical application of TRPA1 antagonist reduced biomarkers of muscle injury (lactate/glucose ratio), spontaneous nociception (rat grimace scale), inflammatory (inflammatory cell infiltration, cytokine levels, myeloperoxidase, and N-acetyl-β-d-glucosaminidase activities) and oxidative (nitrite levels and dichlorofluorescein fluorescence) parameters, and mRNA Trpa1 levels in the muscle tissue. Thus, these results demonstrate that TRPA1 may be a promising anti-inflammatory and antinociceptive target in treating muscle pain after traumatic muscle injury.
... Animal research suggests that t-PBM might exert, via its impact on mitochondria, beneficial effects on several pathophysiological mechanisms implicated in AD, such as oxidative stress [35,36], neuroinflammation [37,38], and deficits in neuroplasticity and brain-derived neurotrophic factor (BDNF) [39][40][41]. NIR can induce short bursts of reactive oxygen species (ROS), leading to the activation of antioxidant mechanisms and the activation of the transcription factor nuclear factor κB (NF-κB), resulting in decreased overexpression of the inducible form of nitric oxide synthase (iNOS) and in a reduction in oxidative stress [32,42,43]. In animal models, NIR light with 600 to 1000 nm reduced neuroinflammation by decreasing proinflammatory cytokines such as IL-6, TNF-α, IL-1β, and IL-8 [44][45][46], decreasing the infiltration of macrophages, and activating microglia and T lymphocytes to the CNS [46]. ...
... Given the ever-increasing prevalence of AD [1] and the lack of effective, easily accessible treatments, the need for novel treatment strategies is dire. t-PBM is an emerging neuromodulation therapy that has a potential to treat AD [21,25,27,28,33,34,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]62,63,[89][90][91], with a favorable safety profile [33,[59][60][61]. Our study will be the first to evaluate the effects of t-PBM in aMCI and mild dementia due to AD in a parallel group, sham-controlled, 8-week randomized, multi-site clinical trial. ...
Background:
Alzheimer's disease's (AD) prevalence is projected to increase as the population ages and current treatments are minimally effective. Transcranial photobiomodulation (t-PBM) with near-infrared (NIR) light penetrates into the cerebral cortex, stimulates the mitochondrial respiratory chain, and increases cerebral blood flow. Preliminary data suggests t-PBM may be efficacious in improving cognition in people with early AD and amnestic mild cognitive impairment (aMCI).
Methods:
In this randomized, double-blind, placebo-controlled study with aMCI and early AD participants, we will test the efficacy, safety, and impact on cognition of 24 sessions of t-PBM delivered over 8 weeks. Brain mechanisms of t-PBM in this population will be explored by testing whether the baseline tau burden (measured with 18F-MK6240), or changes in mitochondrial function over 8 weeks (assessed with 31P-MRSI), moderates the changes observed in cognitive functions after t-PBM therapy. We will also use changes in the fMRI Blood-Oxygenation-Level-Dependent (BOLD) signal after a single treatment to demonstrate t-PBM-dependent increases in prefrontal cortex blood flow.
Conclusion:
This study will test whether t-PBM, a low-cost, accessible, and user-friendly intervention, has the potential to improve cognition and function in an aMCI and early AD population.
... Laser therapy devices (LTDs) operating with near-infrared laser light are increasingly being used in sports medicine and sports physiotherapy to treat, e.g., Achilles tendinopathy [1], carpal tunnel syndrome [2], rotator cuff tendinopathy [3], structural muscle injury [4] and exercise-induced skeletal muscle fatigue [5], to mention only a few indications (see also [6]). For several reasons, users (physicians and physiotherapists) cannot evaluate whether or not such devices emit laser beams according to the specifications provided by the manufacturer and the settings of the device. ...
... Additionally, it can have implications for the significance of clinical studies. Considering that laser therapy is currently debated for the treatment of a variety of medical conditions [1][2][3][4][5][6] and that it remains controversial (e.g., [9,10]), it is highly important that the LTDs used in clinical trials can be trusted. An LTD from the K-laser Cube series was used in at least three clinical studies [11][12][13] in which the light output was not measured. ...
Laser therapy devices (LTDs) operating with near-infrared laser light are increasingly being used in sports medicine. For several reasons, users cannot evaluate whether or not such devices emit laser beams according to the specifications provided by the manufacturer and the settings of the device. In this study, the laser beams from two different LTDs that can be used in sports medicine were thoroughly characterized by measuring the emitted power, pulse shapes and lengths and spatial intensity distributions using professional, high-fidelity laser measurement technology. This was repeated for three units of each LDT independently to distinguish problems of individual units from potential intrinsic instrument design errors. The laser beams from the units of one LTD agreed with the settings of the device, with the measured average power for these units being within 3.3% of the set power. In contrast, the laser beams from the units of the other LTD showed large deviations between the settings and the actual emitted light. This device came with three laser diodes that could be used independently and simultaneously. The average power differed greatly between the units as well as between the laser diodes within each unit. Some laser diodes emitted essentially no light, which could lead to a lack of treatment for patients. Other laser diodes emitted much more power than set at the device (up to 230%), which could result in skin irritations or burning of patients. These findings indicate a need for better standardization and consistency of therapeutic laser light sources.
... The PBMT is defined as a form of light therapy that uses nonionizing light sources, including lasers, light-emitting diodes and/or broadband light, in the visible (400-700 nm) and near-infrared (700-1100 nm) electromagnetic spectrum [17,18]. The first research with PBMT and oxidative stress was conducted in rats, and the results indicated an increase in antioxidant capacity [19], lower inflammatory [20,21] and oxidative damage markers levels [20,21]. ...
... The PBMT is defined as a form of light therapy that uses nonionizing light sources, including lasers, light-emitting diodes and/or broadband light, in the visible (400-700 nm) and near-infrared (700-1100 nm) electromagnetic spectrum [17,18]. The first research with PBMT and oxidative stress was conducted in rats, and the results indicated an increase in antioxidant capacity [19], lower inflammatory [20,21] and oxidative damage markers levels [20,21]. ...
Oxidative stress induced by exercise has been a research field in constant growth, due to its relationship with the processes of fatigue, decreased production of muscle strength, and its ability to cause damage to the cell. In this context, photobiomodulation therapy (PBMT) has emerged as a resource capable of improving performance, while reducing muscle fatigue and muscle damage. To analyze the effects of PBMT about exercise-induced oxidative stress and compare with placebo therapy. Data Sources: Databases such as PubMed, EMBASE, CINAHL, CENTRAL, PeDro, and Virtual Health Library, which include Lilacs, Medline, and SciELO, were searched to find published studies. Study Selection: There was no year or language restriction; randomized clinical trials with healthy subjects that compared the application (before or after exercise) of PBMT to placebo therapy were included. Study Design: Systematic review with meta-analysis. Level of Evidence: 1. Data Extraction: Data on the characteristics of the volunteers, study design, intervention parameters, exercise protocol and oxidative stress biomarkers were extracted. The risk of bias and the certainty of the evidence were assessed using the PEDro scale and the GRADE system, respectively. Results: Eight studies (n = 140 participants) were eligible for this review, with moderate to excellent methodological quality. In particular, PBMT was able to reduce damage to lipids post exercise (SMD = −0.72, CI 95% −1.42 to −0.02, I² = 77%, p = 0.04) and proteins (SMD = −0.41, CI 95% −0.65 to −0.16, I² = 0%, p = 0.001) until 72 h and 96 h, respectively. In addition, it increased the activity of SOD enzymes (SMD = 0.54, CI 95% 0.07 to 1.02, I² = 42%, p = 0.02) post exercise, 48 and 96 h after irradiation. However, PBMT did not increase CAT activity (MD = 0.18 CI 95% −0.56 to 0.91, I² = 79%, p = 0.64) post exercise. We did not find any difference in TAC or GPx biomarkers. Conclusion: Low to moderate certainty evidence shows that PBMT is a resource that can reduce oxidative damage and increase enzymatic antioxidant activity post exercise. We found evidence to support that one session of PBMT can modulate the redox metabolism.
... Furthermore, nonspecific light illumination has been applied in low-level laser therapy (LLLT) for wound healing 53 , tissue regeneration 54 , photothermal therapy 55 , pain management 56 , and anti-inflammatory effects 57 . Light radiation has been reported to regulate ATP production 58 , the NF-κB pathway 59 , and antioxidant activity 60 , thereby offering therapeutic benefits. ...
Traditional chemical interventions regulate cellular processes but often affect non-target biomolecules. Precise and site-specific control is crucial for studying complex systems. Conventional laser-based methods offer high spatial precision and speed but rely on prior sample knowledge and do not apply to highly mobile targets. Real-time precision opto-control (RPOC) overcomes these limits using closed-loop feedback for automated and signal-determined real-time laser activation to regulate chemical processes in live biological samples. This review compares RPOC with other optical control techniques and explores its advancements, applications, and future directions.
... Some molecular mechanisms of interactions between PBM and RANKL/NF-kB are discussed in the literature, mainly in animal models. For example it is shown that low-level laser therapy (LLLT) can modulate the NF-κB signaling pathway in injured muscle tissue, reducing inflammation and promoting muscle recovery by influencing key molecular mediators of the inflammatory response and can activate NF-κB through the production of reactive oxygen species (ROS) in mouse embryonic fibroblasts, suggesting that laser-induced ROS generation plays a crucial role in cellular signaling and gene expression [44,45]. ...
Background: Denosumab is a human monoclonal antibody playing a central role in bone resorption. The impaired bone healing observed in patients on denosumab is linked to the drug’s inhibition of osteoclast activity. Photobiomodulation (PBM) has garnered attention as a potential adjunctive therapy for managing oral complications in patients on denosumab therapy. The aim of this study is to provide a review of the literature regarding the benefits of photobiomodulation therapy in patients taking denosumab while providing a case report of a patient treated with this therapy. Materials and Methods: Key terms were used to search PubMed (MEDLINE), Scopus, and Web of Science, and at last, 25 articles were compared. Following the proposed review, a case of a patient is illustrated. Results: Based on our literature findings, there are no papers regarding the benefits of photobiomodulation therapy in patients taking denosumab specifically, but there are articles regarding photobiomodulation therapy and MRONJ osteonecrosis patients, which can be caused by denosumab. Discussion: Despite all the limitations of the data in the literature, it can be deduced that there are evident benefits of photobiomodulation therapy in patients taking denosumab. The integration of laser-assisted techniques and photobiomodulation into MRONJ management protocols represents a significant evolution in treatment strategies. Conclusions: Further studies are needed to better understand a potential association between odontoclasts (which can cause external root resorption) and neoplastic disease or medication, as well as to explore the role of photobiomodulation in the therapeutic rehabilitation process.
... O Ultrassom Terapêutico (Ibramed, Amparo, Brasil) foi conduzido no modo pulsado, com área de radiação efetiva (ERA) de 1cm², ciclo de trabalho de 50%, frequência de 1MHz, intensidade de 0,8 W/cm² por 6 minutos. A área tratada foi de aproximadamente 2 cm (Rizzi et al., 2006), concentrando-se no foco da injúria em movimentos circulares (Saliba et al., 2007). A formação de substâncias reativas ao ácido tiobarbitúrico (TBARS) durante a reação TBA foi utilizada como índice de peroxidação lipídica (Draper & Hadley, 1990). ...
A fonoforese é apresentada como uma estratégia para aumentar a permeabilidade dos tecidos corporais e consequentemente potencializar a atividade do sistema de defesa antioxidante. Nesta perspectiva, este estudo teve como objetivo verificar efeitos do gel complexado de naringina/β-ciclodextrina associado ao ultrassom terapêutico em biomarcadores oxidativos após lesão musculoesquelética em ratos. Este é um estudo laboratórial de abordagem quantitativa. Ratos wistar machos adultos foram distribuídos com igual proporção em cinco grupos diferentes (n=40): controle, lesão muscular, gel complexado de naringina/β-ciclodextrina, ultrassom terapêutico e ultrassom terapêutico associado ao gel complexado de naringina/β-ciclodextrina. O músculo gastrocnêmio foi lesionado com impacto mecânico. O tratamento foi aplicado com intervalo de 2, 12, 24, 48, 72 e 96 horas após a lesão. A peroxidação lipídica, atividade da superóxido dismutase e atividade da catalase foram avaliadas. O grupo UTP + NAR apresentou redução estatisticamente significativa nos níveis de MDA (1,16 ± 0,16 nmolMDA/mg proteína vs 7,22 ± 0,42 nmolMDA/mg proteína; p<0,05) , atividade da SOD (0,04 ± 0,01 SOD/mg de proteína vs 0,79 ± 0,09 U/mg de proteína; p<0,05 ) e atividade da CAT (0,006 ± 0,001 CAT/mg de proteína vs 0,622 ± 0,032 U/mg de proteína; p<0,05) quando comparado ao grupo não tratado. Não houve diferença estatisticamente significante entre os grupos UTP + NAR e NAR em todas as variáveis analisadas. Esses resultados sugerem que a utilização do gel complexado de naringina/β-ciclodextrina associado ao ultrassom terapêutico após lesão musculoesquelética é eficiente na atenuação da peroxidação lipídica e potencialização do sistema antioxidante.
... 24,40 An appropriate dose of radiation activates this enzyme, promoting cell proliferation and anti-inflammatory potential. 41,42 However, exceeding the optimal radiation dosage can result in increased oxidative stress and excessive NF-kB activation. 43 Another transcription factor that undergoes modification in response to PBMT is the hypoxia-inducible factor (HIF), a small protein involved in the response of cells to hypoxia. ...
... Currently, the regulatory effects of parenchymal border macrophages (PBM) on ROS are still controversial. Some studies have shown that PBM enhanced the ROS production by activating the superoxide converting system, 174,175 whereas other studies have suggested the opposite. 176 A recent study found that PBM increased ROS levels in normal neurons but reduced it in oxidatively stressed neurons. ...
The brain diseases account for 30% of all known diseases. Pharmacological treatment is hampered by the blood–brain barrier, limiting drug delivery to the central nervous system (CNS). Transcranial photobiomodulation (tPBM) is a promising technology for treating brain diseases, due to its effectiveness, non-invasiveness, and affordability. tPBM has been widely used in pre-clinical experiments and clinical trials for treating brain diseases, such as stroke and Alzheimer’s disease. This review provides a comprehensive overview of tPBM. We summarize emerging trends and new discoveries in tPBM based on over one hundred references published in the past 20 years. We discuss the advantages and disadvantages of tPBM and highlight successful experimental and clinical protocols for treating various brain diseases. A better understanding of tPBM mechanisms, the development of guidelines for clinical practice, and the study of dose-dependent and personal effects hold great promise for progress in treating brain diseases.
... In a study, it was shown that LLLT induces analgesia by decreasing bradykinin level and activity of C fibers, and also by stimulating endogenous endorphin(βendorphin)synthesis and changing the pain threshold [19]. Accordingto Rizzi et al. [20], LLLT has an effect on nuclear factor kappa B (NF-kB); it can also reduce the inflammatory response caused by trauma and block the effects of the release of reactive oxygen species (ROS) and activation of NF-kB. The same effect may have been achieved in our study on wound healing at the apical region. ...
The aim of this study was to compare the effect of ozone and low-level-laser therapy (LLLT) on postoperative pain after root canal treatment in symptomatic apical periodontitis on vital teeth. Eighty patients were divided into four groups using a web program as follows: LLLT placebo (mock laser therapy), LLLT, Ozone placebo (mock ozonated water irrigation), and Ozone. Postoperative pain levels for 7 days after treatment and percussion pain levels at the 7th day were recorded on the visual analog scale. A regression analysis, Cochran’s Q test, Chi-square test, Kruskal-Wallis tests were performed to analyze the data (P=.05). A regression analysis demonstrated that the most effective variables are “group” and “jaw” (P=0.01). Pain in the lower jaw is higher than the upper jaw. There was difference between the groups on postoperative pain at the days 1, 2, and 3; however, there was no significant difference on other days. LLLT and ozone groups had less postoperative pain and pain on percussion. Low-level laser and ozone therapy are useful methods on postoperative-pain in vital symptomatic teeth ,but they don’t have superiority to each other.
... NO can also diffuse outside, as a messenger for several pathways including vasodilation. PBM was shown to reduce oxidative stress [14][15][16][17] and inflammation [18][19][20][21] and to modulate cell signaling [9,[22][23][24][25] and gene expression [26][27][28]. ...
Photobiomodulation (PBM) relies on the pathophysiological mechanism whereby red to near-infrared light can target mitochondrial activity and promote ATP synthesis. Preclinical and clinical studies have shown promising results in treating intermediate age-related macular degeneration (AMD), since PBM can produce photochemical reactions in endogenous retinal chromophores. Currently, PBM is approved by the Food and Drug Administration and by the European Medicines Agency for the treatment of intermediate AMD. This narrative review aimed to evaluate the available evidence on the effectiveness and safety of PBM in treating intermediate AMD.
A comprehensive search was conducted using the PubMed database, employing the keywords “photobiomodulation” and “age-related macular degeneration.” All English-language studies published up to June 2023 were reviewed, and the search was expanded to include relevant references from selected articles. The included publications were analyzed for this review.
The available studies on PBM in AMD demonstrated promising but inconsistent results. PBM showed potential in improving best-corrected visual acuity (BCVA) and contrast sensitivity (CS) in patients with AMD. Some studies also suggested a reduction in AMD lesions, such as drusen volume. However, the long-term efficacy and optimal treatment parameters of PBM in AMD remained to be fully determined due to the limitations of the available studies. These included variations in irradiation techniques, wavelengths, exposure times, and treatment sessions, making it challenging to generalize the effectiveness of PBM. Furthermore, the lack of accurate classification of AMD phenotypes in the available studies hindered the understanding of which phenotypes could truly benefit from this treatment. Finally, the strength of evidence varied among studies, with limited sample sizes, unpublished results, and only three randomized sham-controlled trials.
Currently, the effectiveness of PBM in promoting drusen resorption or preventing progression to advanced forms of AMD, as observed in the cited studies, remains uncertain.
... The findings suggest that the therapeutic approach may help restore the muscle after crush injury. Literature reviewes showed that photobiomodulation promotes recovery of the injured muscle, 13 increases muscle mass, significantly decreases oxidative damage markers, augments collagen synthesis, 14,15 increases mitochondrial activity in muscular fibers, activates fibroblasts and macrophages stimulating angiogenesis, 16 and improves gene expression of biochemical inflammatory markers. ...
Severe peripheral nerve and muscle injuries are a highly prevalent condition for both civilians and military personnel caused by traffic accidents, work injuries, acts of violence, as well as combat events. Peripheral nerve injury is a substantial problem that annually affects more than several millions of people all over the world. For most patients who suffer from severe peripheral nerve injuries spontaneous recovery may eventually occur, but it is slow and frequently incomplete. Effective posttraumatic nerve repair and decrease or prevention of corresponding muscle atrophy remain a great challenge to restorative medicine. A certain clinical interest began to appear in the potential therapeutic value of laser phototherapy (new name – laser photobiomodulation) for regeneration enhancement of injured peripheral nerve as well as for restoration or prevention of denervated muscle atrophy. Although a pioneering report regarding the effects of laser phototherapy on the regeneration of traumatically injured peripheral nerves was published in the late 1970s,1 it is only since the end of past century - early 2000s that scientific interest in this therapeutic approach for neural rehabilitation has appeared, leading to publication of several studies that have shown positive effects of phototherapy on peripheral nerve regeneration.2 [...]
... The treatments were performed 7 consecutive days for every month. NIR light and white light can stimulate ROS generation by 10-20%, which is the normal for cells, and such parameters were shown to provide positive effects on cells and tissues, while not causing cell phototoxicity [30][31][32][33][34][35][36][37][38][39][40]. ...
... Animal research suggests that tPBM might also exert, via its impact on mitochondria, beneficial effects on several other pathophysiological mechanisms implicated in MDD, such as oxidative stress [34][35][36][37][38], neuroinflammation [39][40][41][42][43], and deficits in neuroplasticity and brain derived neurotrophic factor (BDNF) [44][45][46]. NIR can induce short bursts of reactive oxygen species (ROS) leading to the activation of antioxidant mechanisms and the activation of the transcription factor nuclear factor κB (NF-κB), resulting in decreased overexpression of the inducible form of nitric oxide synthase (iNOS) and reduction of oxidative stress [32,47,48]. In animal models, NIR light (600 to 1000 nm) reduced neuroinflammation by decreasing proinflammatory cytokines such as IL-6, TNF-α, IL-1β, and IL-8 [49][50][51], and decreasing the infiltration of macrophages, activated microglia, and T lymphocytes to the CNS [51]. ...
We report on the rationale and design of an ongoing National Institute of Mental Health (NIMH) sponsored R61-R33 project in major depressive disorder (MDD). Current treatments for MDD have significant limitations in efficacy and side effect burden. There is a critical need for device-based treatments in MDD that are efficacious, well-tolerated, and easy to use. This project focuses on the adjunctive use of the transcranial photobiomodulation (tPBM) with near-infrared (NIR) light for the treatment of MDD. tPBM with NIR light penetrates robustly into the cerebral cortex, stimulating the mitochondrial respiratory chain, and also significantly increases cerebral blood flow (CBF). In the R61 phase, we will conduct target engagement studies to demonstrate dose-dependent effects of tPBM on the prefrontal cortex (PFC) CBF, using the increase in fMRI blood-oxygenation-level-dependent (BOLD) signal levels as our Go/No-go target engagement biomarker. In the R33 phase, we will conduct a randomized clinical trial of tPBM vs. sham in MDD to establish the target engagement and evaluate the association between changes in the biomarker (BOLD signal) and changes in clinical symptoms, while also collecting important information on antidepressant effects, safety, and tolerability. The study will be done in parallel at New York University/the Nathan Kline Institute (NYU/NKI) and at Massachusetts General Hospital (MGH). The importance of this study is threefold: 1. it targets MDD, a leading cause of disability worldwide, which lacks adequate treatments; 2. it evaluates tPBM, which has a well-established safety profile and has the potential to be safe in at-home administration; and 3. it uses fMRI BOLD changes as a target engagement biomarker. If effects are confirmed, the present study will both support short-term clinical development of an easy to scale device for the treatment of MDD, while also validating a biomarker for the development of future, novel modulation strategies.
... Laser therapy devices (LTDs) operating with near-infrared laser light are increasingly being used in sports medicine and sports physiotherapy to treat, e.g., Achilles tendinopathy [1], carpal tunnel syndrome [2], rotator cuff tendinopathy [3], structural muscle injury [4] and exercise-induced skeletal muscle fatigue [5], to mention only a few indications (see also [6]). For several reasons the users (physicians and physiotherapists) cannot evaluate whether or not such devices emit laser beams according to the specifications provided by the manufacturer and the settings of the device. ...
Laser therapy devices (LTDs) operating with near-infrared laser light are increasingly being used in sports medicine. For several reasons the users cannot evaluate whether or not such devices emit laser beams according to the specifications provided by the manufacturer and the settings of the device. In this study the laser beams from two different LTDs that can be used in sports medicine were thoroughly characterized by measuring the emitted power, pulse shapes and lengths, and spatial intensity distributions using professional, high-fidelity laser measurement technology. This was repeated for three units of each LDT independently to distinguish problems of individual units from potential intrinsic instrument design errors. The laser beams from the units of one LTD agreed with the settings at the device, with the measured average power for these units being within 3.3% of the set power. In contrast, the laser beams from the units of the other LTD showed large deviations between the settings and the actual emitted light. This device came with three laser diodes that could be used independently and simultaneously. The average power differed greatly between the units as well as between the laser diodes within each unit. Some laser diodes emitted essentially no light, which could lead to a lack of treatment of patients. Other laser diodes emitted much more power than set at the device (up to 230%) that could result in skin irritations or burnings of patients. These findings indicate a need for better standardization and consistency of therapeutic laser light sources.
... Aimbre et al. [38] noted that LLLT reduced neutrophil influx and the expression of IL-1β micro-ribonucleic acid. LLLT can inhibit nuclear factor kappa B (NF-κB), the key inflammatory transcription factor, and the related signaling pathways [39,40]. LLLT can also suppress other important mediators of inflam-mation, namely, macrophage-associated inflammatory proteins and pro-inflammatory cytokines [41]. ...
Little is known about alternative treatment options for rhinosinusitis (RS). We aimed to evaluate the efficacy of low-level laser therapy (LLLT) for RS in experimentally induced rabbit models of RS. A total of 18 rabbits were divided into four groups: a negative control group (n = 3), an RS group without treatment (n = 5, positive control group), an RS group with natural recovery (n = 5, natural recovery group), and an RS group with laser irradiation (n = 5, laser-treated group). Computed tomography and histopathological staining were performed for each group. mRNA and protein expression levels of local cytokines (IFN-γ, IL-17, and IL-5) were also measured. Tissue inflammation revealed a significant improvement in the laser-treated group compared with the RS and natural recovery groups (p < 0.01). In addition, sinus opacification in the CT scans and cytokine expression was reduced in the laser-treated group, though without statistical significance. LLLT could be an effective option for the management of RS concerning radiological, histological, and molecular parameters.
... Oberoi et al. (2014 ) reported the consistent findings on the addition of LLLT to HNC treatment regimen were reduction in the pain, severity duration and prevalence of oral mucositis. More specifically, Rizzi et al. (2006 ) demonstrated that LLLT inhibited trauma-induced NF-κb activation, suggesting this may be a potential target of LLLT. Decrease in severity of oral mucositis following treatment with LLLT was associated with decrease in pro-inflammatory cytokines IL-1β and TNF-α (Oton- Leite et al. 2015 ). ...
Radiation therapy is a vital integrated part of modern comprehensive cancer management. Aside from the typical use of radiotherapy in treatment of cancer, low-dose radiation (LDR), typically <100 mGy, shows the capacity to improve wound healing by promoting fibroblast-to-myofibroblast differentiation, matrix deposition, keratinocyte proliferation and angiogenesis. Moreover, animal studies have shown LDR attenuates systemic acute inflammatory response by regulating inflammatory cytokines, thus alleviating damage associating with chronic diabetic and burn wounds. Wounds can be classified as open or closed. Open wounds, such as cuts, burns or ulcers, can arise from external factors such as accidents, surgery and trauma or internal factors, such as diabetes mellitus, whereas closed wounds may occur due to blunt force trauma. Additionally, wounds can be either acute or chronic, depending on their healing capacity. These disruptions of the skin’s structural and functional integrity go through four distinct phases to achieve complete wound healing, namely, haemostasis, inflammation, cellular migration and proliferation and remodelling. Photobiomodulation and low-dose ionizing radiation have been studied for their effects on the cellular and molecular processes involved in wound healing. Similarly, both methods of low-dose radiation treatment have also been examined for their cancer therapy-associated adverse effects. In this paper, the molecular and cellular effects of low-dose radiation on wound healing and cancer cells are discussed. Additionally, the protective effects of low-dose radiation against conventional cancer treatments such as high-dose radiation and chemotherapy are also discussed.
... However, a longer wavelength light improves muscle function. [23][24][25][26][27] This is the likely mechanism for improved hive thermoregulation. In support of this, 670 nm light exposures that stabilized hive temperature were correlated with increased ATP. ...
Objective: Bee populations are under threat from diverse sources from climate change to insecticide use. These culminate in physiological stress undermining mitochondrial function. In laboratory environments, mitochondrial stress can be ameliorated by long wavelength light that protects insects individually against stress. In this study, we ask if these results can be translated to large insect communities and complex environments in the form of field honeybee hives. Materials and methods: We embed 670 nm light devices into honeybee hives in the field, and in sampled populations measure mitochondrial function, resistance to insecticide exposure, and the maintenance of hive temperatures in challenging summer conditions. Results: We show that 670 nm light increases the mitochondrial function and protects bees when they are exposed to imidacloprid in the winter supplementary feed. Hives with 670 nm lights maintained stable temperatures compared with controls in adverse weather conditions. Conclusions: This proof-of-principal study opens the door to widespread use of long wavelength light to protect honeybee hives from the increasing threats undermining their physiology that can cause colony collapse.
... A possible explanation for the analgesic effect of LLLT is its ability to modulate various signaling pathways and physiological mechanisms involved in analgesia, such as increasing β-endorphin levels and modulating pain-related biochemicals, including substance P, TNF-alpha, and cyclooxygenase-2 [25][26][27]. Animal studies indicate that preoperative LLLT may locally act on the oxidative stress pathway to prevent ischemic muscle damage, decreasing the re-release of ROS, while increasing the levels of antioxidants and heat shock proteins [28]. ...
Objective
The aim of this study is to compare the effect of photobiomodulation with low-level laser therapy (LLLT) and nimesulide on inflammatory parameters, biomarkers of oxidative stress and inflammation, and quality of life after lower third molar (L3M) surgery.
Material and methods
A randomized, two-factor, triple-blind, controlled, split-mouth clinical trial was performed with 40 volunteers who required bilateral L3M removal. Patients were allocated depending on the use or not of 100 mg nimesulide 1 hbefore surgery, as well as the use or not of LLLT in the preoperative period.
Results
Pain peaks occurred after 6 h (nimesulide-placebo [N-P] group) and 8 h (nimesulide group). In the N-P group, LLLT resulted in significantly lower mean pain scores than the subgroup without LLLT after 4 h (p = 0.009) and 6 h (p = 0.048). As for edema, a shorter distance between the mandibular angle and the outer canthus of the eyes after 7 days (p = 0.037) and a smaller cumulative effect (p = 0.036) were observed in the N-P group associated with LLLT. A direct effect between LLLT (p = 0.047) and a reduction in the mean scores of overall dissatisfaction with quality of life was detected.
Conclusions
Preemptive use of nimesulide only delayed peak pain. LLLT reduced edema, trismus, and contributed to a better perception of quality of life. Nimesulide inhibits peroxidation by increasing GSH and stopping neutrophil migration. The benefit of the association of both strategies was not superior to the use of LLLT alone.
Clinical relevance
Translational study with impact on clinical-surgical protocols involving L3M surgery related to pharmacological and non-pharmacological methods.
... In the case of LLLT stimulation, we observe a typical reaction consistent with the Arndt-Schulz law. The appropriate dose of radiation leads to the activation of the enzyme and increases the proliferative and antiinflammatory potential [96,97]. However, exceeding the radiation dose led to increased oxidative stress and an over-abundant activation of NF-κB [98]. ...
Low-level laser therapy (LLLT) has become an important part of the therapeutic process in various diseases. However, despite the broad use of LLLT in everyday clinical practice, the full impact of LLLT on cell life processes has not been fully understood. This paper presents the current state of knowledge concerning the mechanisms of action of LLLT on cells. A better understanding of the molecular processes occurring within the cell after laser irradiation may result in introducing numerous novel clinical applications of LLLT and potentially increases the safety profile of this therapy.
... Light power density was adjusted to be 30 mW/cm 2 , and the light irradiation time was 5 min for each sample, resulting in the irradiation dose of 9 J/cm 2 . These light power density and dose were chosen because NIR light with such parameters was shown to provide positive effects on cells and tissues, while not causing cell phototoxicity [48][49][50][51][52][53][54][55][56]. It should be noted that one session of CW irradiation was used to explore the biochemical pathways initiated by light but not to determine the best parameters for LLLT. ...
Background
Low-intensity light can decelerate neurodegenerative disease progression and reduce amyloid β (Aβ) levels in the cortex, though the cellular and molecular mechanisms by which photobiomodulation (PBM) protects against neurodegeneration are still in the early stages. Microglia cells play a key role in the pathology of Alzheimer’s disease by causing chronic inflammation. We present new results concerning the PBM of both oxidative stress and microglia metabolism associated with the activation of metabolic processes by 808 nm near-infrared light.
Methods
The studies were carried out using healthy male mice to obtain the microglial cell suspension from the hippocampus. Oligomeric β-amyloid (1-42) was prepared and used to treat microglia cells. Light irradiation of cells was performed using diode lasers emitting at 808 nm (30 mW/cm ² for 5 min, resulting in a dose of 10 J/cm ² ). Mitochondrial membrane potential, ROS level studies, cell viability, apoptosis, and necrosis assays were performed using epifluorescence microscopy. Phagocytosis, nitric oxide and H 2 O 2 production, arginase, and glucose 6-phosphate dehydrogenase activities were measured using standard assays. Cytokines, glucose, lactate, and ATP were measurements with ELISA. As our data were normally distributed, two-way ANOVA test was used.
Results
The light induces a metabolic shift from glycolysis to mitochondrial activity in pro-inflammatory microglia affected by oligomeric Aβ. Thereby, the level of anti-inflammatory microglia increases. This process is accompanied by a decrease in pro-inflammatory cytokines and an activation of phagocytosis. Light exposure decreases the Aβ-induced activity of glucose-6-phosphate dehydrogenase, an enzyme that regulates the rate of the pentose phosphate pathway, which activates nicotinamide adenine dinucleotide phosphate oxidases to further produce ROS. During co-cultivation of neurons with microglia, light prevents the death of neurons, which is caused by ROS produced by Aβ-altered microglia.
Conclusions
These original data clarify reasons for how PBM protects against neurodegeneration and support the use of light for therapeutic research in the treatment of Alzheimer’s disease.
Graphical Abstract
... Laser has been previously used in periodontology for its antibacterial and anti-inflammatory effects in the treatment of periodontal and peri-implant diseases [17][18][19][20] . PBM has also been found to be able to modulate the immune response and reduce chronic inflammation 19,[21][22][23] , and can therefore potentially facilitate periodontal tissue repair. ...
Objective:
To determine the effect of different energy densities of near infrared diode lasers with wavelengths of 810 or 940 nm on the proliferation and survival of periodontal ligament derived stem cells (PDLSCs).
Methods:
After isolation and characterisation, PDLSCs were cultured in clear 96-well plates. Each well was irradiated by either 810 nm (L1) or 940 nm (L2) lasers, with energy densities of 0.5, 1.5 and 2.5 J/cm2 and an output power of 100 mW. A non-irradiated well was used as a control. Cellular viability was measured 24 hours after irradiation using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and proliferation was measured 24, 48 and 72 hours after irradiation using trypan blue staining and counting. Propidium iodide (PI) staining was used to identify any pyknotic nuclei or nuclear fragmentation 72 hours after irradiation.
Results:
An increase in viability was observed only in the group with the 940 nm laser irradiation at energy density of 2.5 J/cm2 (P < 0.001). The proliferation of cells was significantly increased in the group with 940 nm laser irradiation at energy density of 2.5 J/cm2 at all the time points examined in comparison to other groups (P < 0.001). PI staining showed no change in cell nuclei in any of the groups.
Conclusion:
Irradiation of PDLSCs with a 940 nm laser at an energy density of 2.5 J/cm2 could promote efficient cell proliferation.
... In agreement with this finding, other studies found that PBM decreased the IL-1β in muscle tissue after cryoinjury [35,36] and exercise-induced damage [14]. This inflammation reduction by PBM could be one of the factors related to the decrease of lipoperoxidation [12,37]. Liver damage in BDL rats is maximized by the inflammatory process and increases reactive oxygen species (ROS) which can lead to complications in the various organs and systems of the body, including the musculoskeletal system [29,38,39]. ...
Photobiomodulation (PBM) might be an intervention method to mitigate sarcopenia in cirrhotic patients. Given the lack of research on this issue, the goal of this study was to evaluate possible beneficial effects of PBM on the structural and functional properties of skeletal muscle from cirrhotic rats. Cirrhosis was induced by secondary bile duct ligation (BDL). Wistar rats were randomized into four groups: sham-operated control (Sham), Sham + PBM, BDL, and BDL + PBM. After cirrhosis induction, a dose of PBM (1 J; 100mW; 10 s; 880 nm; 6 × per week) was applied to each quadriceps, from the 15th to the 45th day after surgery. The locomotor ability was performed using an open-field task. The muscle structure was analyzed using histological methods. Cell damage was also evaluated assessing oxidative stress and DNA damage markers, and IL-1β pro-inflammatory interleukin by immunohistochemical analysis. An increase in the number of crossings was observed in the BDL + PBM group in relation to BDL. The BDL group showed muscle atrophy and increased IL-1β in relation to Sham, while in the BDL + PBM group, the fiber muscle was restructured and there was a decrease of IL-1 β. TBARS increased in the liver and muscle tissues in the BDL group and decreased it in the BDL + PBM group. SOD increased while CAT decreased in the BDL + PBM group in relation to the BDL group. No genotoxic or mutagenic effect was observed for PBM treatment. PBM improved the locomotion and the morphology of the muscle fibers, decreasing oxidative stress and inflammation, without causing DNA damage in cirrhotic rats.
... HeNe laser stimulated ATP synthesis in mitochondria [1]. Since then, a wide range of methodologies have been used to study the effects of PBM, ranging from biological methods such as histology [2] and western blot analysis [3], to the techniques of spectrophotometry [4], Raman spectroscopy [5], and fluorescence [6]. Many of these studies focus on the products, or downstream effects of cellular processes, rather than the immediate photon absorption steps by proteins that initiate the PBM processes. ...
Photobiomodulation (PBM) describes the use of low irradiance light in the red to near-infrared wavelength range to stimulate biological effects in tissue, and many biological and spectroscopic techniques are used to study PBM. However, these techniques focus on the products or downstream effects rather than the electronic transitions that initiate the PBM processes. This study presents a novel approach to studying low irradiance light exposures on individual proteins and/or protein complexes by combining a continuous wave (CW) laser diode with femtosecond transient absorption spectroscopy (TAS), coined here as CW-TAS, and tests the system on reduced cytochrome c (Cyt c) for proof of principle.
TAS was conducted using a 532-nm excitation pump beam and a 350–600 nm supercontinuum probe. CW laser diodes with wavelengths of 450 nm, 635 nm, and 808 nm were interchangeably fiber coupled into the HELIOS Fire. Samples of Cyt c were tested by TAS using a pump power of 15 μW, both with and without CW exposure. CW exposures were carried out with irradiances of 1.60 and 3.20 mW/cm², except for 808 nm, which was only tested at 1.60 mW/cm². Both kinetic and global analyses were performed on the TAS data and the time constants for sets with and without CW exposures were compared.
The TAS data for Cyt c with the full dosage of CW exposures did not alter the TAS data distinguishably from the control data. No new electronic transient signals were observed beyond the background when testing Cyt c with the CW exposures. Kinetic analysis confirmed that existing transients did not deviate beyond uncertainty. Global time constants for Cyt c were calculated to be 0.25 ± 0.03 ps and 5.1 ± 0.3 ps for the control study, and the time constants for the CW exposed Cyt c were not significantly different.
This study concludes that CW irradiation, at doses delivered, does not alter the transient absorption data of Cyt c. The CW-TAS method provides a new tool for studying PBM effects in other proteins and protein complexes that might respond to the CW wavelengths, such as Complex IV, in future studies.
Craniofacial fractures pose complex medical and surgical challenges. Prolonged wound healing complicates surgical reconstruction, highlighting the need for methods to enhance tissue healing. This research evaluated the effects of photobiomodulation (PBM) therapy on edema, trismus, and pain following mandibular fracture surgery. This study was approved by th e Kasturba Hospital and Kasturba Medical College Institutional Ethics Committee (IEC: 219/2022). Thirty‐two participants were signed up and split into two groups, one receiving PBM. Ten 660 nm LEDs with an energy density of 9 J/cm ² , Power density (irradiance) of 50 mW/cm ² , and nine 905 nm LEDs with an energy density of 13.5 J/cm ² , power density (irradiance) of 75 mW/cm ² . With a total power of 235 mW, the total dose was 42.3 J, a spot Size of 3.8 cm ² , and pulsed at 156 Hz. The mandibular body and angle area were irradiated from the outer skin surface of the Jaw region. The therapy lasted for 3 min and was given for 4 consecutive days starting from the day after surgery. The present study evaluates pain thresholds using an algometer. The facial swelling was measured at two distinct points, the ear's tragus to the labial commissure (T‐LC) and the outer canthus of the eye to the mandible's angle (OC‐AM), using a ruler. Mouth opening was measured for trismus using a vernier calliper. There was no significant reduction in pain (−0.34 vs. −0.09; p = 0.079) or edema (T‐LC: 2.44 vs. 2.13; p = 0.771, OC‐AM 2.31 vs. 0.69; p = 0.185) in the PBM‐treated group compared to the control group. However, trismus reduction was significantly better in the PBM group (−3.25 vs. −1.31; p < 0.001). In summary, a specific PBM protocol can effectively reduce trismus during recovery from mandibular fractures, with the potential for future optimization to address pain and edema.
Abnormal biomechanics plays a central role in the development of knee osteoarthritis (KOA). Low-intensity laser therapy (LILT) is considered an applicable method for the treatment of osteoarthritis. Current research on LILT for the treatment of KOA has focused on the regeneration of articular cartilage. Its biomechanical changes in periarticular tissues have been less well studied, and its role in improving abnormal joint biomechanics is unclear. This study aimed to investigate the role of LILT in improving the biomechanical properties of muscle and cartilage in KOA joints to alleviate cartilage degradation. In this study, a semiconductor laser with a wavelength of 808 nm was used to perform laser interventions in a KOA rat model 3 days per week for 6 weeks. The results of muscle stretch tests showed that LILT could significantly reduce the modulus of elasticity of KOA soleus muscle. Hematoxylin and eosin staining showed that LILT significantly increased the cross-sectional area of the soleus muscle fibers. This suggests that LILT alleviated KOA-induced soleus muscle atrophy and restored the mechanical properties of the muscle tissue. The results of compressive elastic modulus and electrical impedance characterization of cartilage showed that laser intervention significantly increased the elastic modulus and resistivity of cartilage. Results from safranin o-fast green staining and immunohistochemistry showed that LILT significantly increased the synthesis of type II collagen in the cartilage matrix. This may be one of the potential mechanisms by which LILT improves the mechanical properties of cartilage. In addition, immunohistochemistry also showed that LILT reduced the expression of matrix metalloproteinase-13 in cartilage and effectively inhibited the degradation of the cartilage matrix in KOA. In conclusion, the present study demonstrated that LILT alleviated the abnormal biomechanics of KOA joint tissues by improving the mechanical properties of joint muscles and cartilage, thereby slowing down the degradation of KOA cartilage.
Photobiomodulation involves the use of low-power lasers or lights to activate intracellular or extracellular chromophores to stimulate cellular signaling. Over the past 50 decades, research has demonstrated that laser or light therapy has the potential to improve wound healing and reduce pain and inflammation. In recent years, the term photobiomodulation has become widely recognized. This chapter describes the mechanisms of action of photobiomodulation at the cellular level, including some examples of our data showing that photobiomodulation enhances cell differentiation.
Skeletal muscle fatigue, characterized by a temporary decline in the ability to generate force or power output, encompasses peripheral and central components, each with distinct mechanisms and implications for physical performance. Peripheral fatigue originates in the muscle and is attributed to factors such as energy depletion, accumulation of metabolic byproducts, and impaired calcium handling, which directly affect muscle contraction efficiency. On the other hand, central fatigue involves a reduction in voluntary activation of muscles, stemming from alterations in neurotransmitter levels and neural drive from the central nervous system. Understanding the intricate balance between central and peripheral fatigue is crucial for developing strategies to enhance athletic performance, manage fatigue in clinical populations, and improve overall functional capacity. This dual perspective on muscle fatigue broadens our comprehension of the limits of human performance but also opens avenues for targeted interventions to mitigate fatigue’s impact.
Despite considerable advances in antineoplastic treatments, their adverse effects persist, negatively impacting the quality of life of patients undergoing chemotherapy and radiotherapy regimens. One of these complications is oral mucositis (OM), characterized by inflammation and ulceration of the mucosa lining the oral cavity. As this condition progresses, routine actions such as brushing teeth, eating and drinking liquids become difficult, in addition to causing a risk of systemic infections and even costs associated with maintaining and interrupting antineoplastic treatment. Therefore, the objective of this chapter is to address how photobiomodulation (PBM) can play a crucial role in the prevention and effective treatment of OM in patients undergoing cancer treatment. Initially, we will give a brief explanation about OM, followed by a comprehensive description of PBM, covering its definition, biological effects directly in the irradiated region, mechanisms of action, indications, and contraindications, including highlighting the protocols widely used for prevention and treatment, cost-effectiveness of the of PBM and precautions for head and neck cancer.
Mitochondria play a vital role in the nervous system, as they are responsible for generating energy in the form of
ATP and regulating cellular processes such as calcium (Ca2+) signaling and apoptosis. However, mitochondrial
dysfunction can lead to oxidative stress (OS), inflammation, and cell death, which have been implicated in the
pathogenesis of various neurological disorders. In this article, we review the main functions of mitochondria in
the nervous system and explore the mechanisms related to mitochondrial dysfunction. We discuss the role of
mitochondrial dysfunction in the development and progression of some neurological disorders including Parkinson's disease (PD), multiple sclerosis (MS), Alzheimer's disease (AD), depression, and epilepsy. Finally, we
provide an overview of various current treatment strategies that target mitochondrial dysfunction, including
pharmacological treatments, phototherapy, gene therapy, and mitotherapy. This review emphasizes the
importance of understanding the role of mitochondria in the nervous system and highlights the potential for
mitochondrial-targeted therapies in the treatment of neurological disorders. Furthermore, it highlights some
limitations and challenges encountered by the current therapeutic strategies and puts them in future perspective.
A femtosecond laser creates an intrastromal lenticule while the eye is immobilized by vacuum in refractive corneal lenticule extraction to correct myopia. Suction loss has a 0.72% overall incidence and may result in an incomplete cut; the procedure can then be completed using the same or different techniques. While previous laser platforms used corneal suction, the recent lenticule extraction (CLEAR) application for the Ziemer Z8 femtosecond laser (Ziemer Group, Port) uses scleral suction; studies on suction loss with this vacuum system are lacking. A total of 652 eyes from 357 CLEAR patients were thus included in a consecutive, single-institution, retrospective study. Suction loss occurred in three patients’ left eyes (0.46%) due to a strong involuntary eyelid contraction. After an early suction loss in patient #1, the procedure was successfully repeated with the same parameters. Suction loss occurred after the completion of the posterior cut and at 44% of the anterior cut in patient #2. The laser procedure appeared to have been completed in patient #3, but the lenticule had not been delineated temporally due to false suction on the conjunctiva. Thin flap femtosecond laser in situ keratomileusis (LASIK) was used to complete the refractive procedure in patients #2 and #3. Uncorrected distance visual acuity was 20/20 or better in all three eyes at 6 months. Finally, suction loss during CLEAR was uncommon and had a favorable prognosis. Repeat lenticule extraction or femtosecond LASIK can be performed on the same day to complete the treatment.
The objective of the current study was to evaluate Low-level laser therapy (LLLT) on the healing of incisional wounds following ovariohysterectomy in rats, by means of subjective histopathological and immunohistochemical analysis. A total of 72 female Wistar rats were categorized into four treatment groups (Group I; sacrification 4 hours following only one LLLT application, Group II; sacrification 7 days following only one LLLT application, Group III; sacrification 4 hours after two LLLT applications, and Group IV; sacrification 7 days after two LLLT applications). Each group was further divided into four different doses subgroups (Group Control [C, off mode LLLT application], L1 [1 J/cm2], L3 [3 J/cm2], and L6 [6 J/cm2]), with equal representation in each subgroup. Ovariohysterectomy was employed using two 2-cm-length midline abdominal incisions in the left and right sides of line alba. The Group C was assigned to the left side incision to each rat in the study. After irradiation, the tissue was subjected to histopathological analysis to determine the extent of mononuclear cell infiltration, edema, and epithelialization. Additionally, immunohistochemical analysis was performed to evaluate the expression of proliferating cell nuclear antigen (pCNA) and inducible nitric oxide synthase (iNOS). Group L1 and L3 significantly decreased mononuclear cell infiltration compared with Group C in all treatment groups (p < 0.05). Group L3 significantly decreased edema compared with Group C in all groups except for treatment Group I (p < 0.05). Group L2 and L3 significantly increased epithelization in treatment Group IV (p < 0.05). Moreover, Group L2 and L3 significantly increased pCNA in all groups, while L2 and L3 significantly decreased iNOS expression in treatment Group II, III, and IV (p < 0.05). However, no statistical difference was found between subgroups of treatment Group I in iNOS expiration (p > 0.05). The results of the current examination demonstrated that LLLT can modulate mononuclear cell infiltration and edema, and improve epithelization, as well as increase pCNA expression, whereas decrease iNOS expression during the wound healing process, therefore enhancing wound healing following ovariohysterectomy in rats.
Based on the review of the literature, this article examines the potential therapeutic benefits of photobiomodulation therapy (PBMT) or low-level laser therapy (LLLT) for the treatment of cardiovascular disorders. The methodology involved searching PubMed, Google Scholar, and Central databases for relevant articles published from inception till date. The articles included in this review were preclinical and clinical studies investigating the effects of PBMT and LLLT on the heart. The article summarizes the findings of nineteen studies investigating the effects of PBMT and LLLT on various parameters related to heart failure (HF) and myocardial infarction (MI), including inflammation, oxidative stress, angiogenesis, cardiac function, and remodeling. The studies suggest that PBMT and LLLT have potential therapeutic benefits for the treatment of cardiovascular diseases and could be used in combination with traditional pharmacological therapies to enhance their effects or as a stand-alone treatment for patients who are not responsive to or cannot tolerate traditional therapies. In conclusion, this review article highlights the promising potential of PBMT for the treatment of HF and MI and the need for further research to fully understand its mechanisms of action and optimize treatment protocols.
Background
Low-intensity light can decelerate neurodegenerative disease progression and reduce amyloid β (Aβ) levels in the cortex, though, the cellular and molecular mechanisms by which photobiomodulation protects against neurodegeneration are still in the early stages. Microglia cells play a key role in the pathology of Alzheimer's disease by causing chronic inflammation. We present new results concerning the photobiomodulation of both oxidative stress and microglia metabolism associated with the activation of metabolic processes by 808 nm near-infrared light.
Methods
The studies were carried out using healthy male mice to obtain the microglial cell suspension from the hippocampus. Oligomeric β-amyloid (1–42) was prepared and used to treat microglia cells. Light irradiation of cells was performed using diode lasers emitting at 808 nm (30 mW/cm² for 5 min, resulting in the dose of 10 J/cm²). Mitochondrial membrane potential, ROS level studies, cell viability, apoptosis and necrosis assays were performed using epifluorescence microscopy. Phagocytosis, nitric oxide and H2O2 production, arginase and glucose 6-phosphate dehydrogenase activities were measured using standard assays. Cytokines, glucose, lactate, and ATP were measurements with ELISA. As our data were normally distributed, Student’s t-test was used.
Results
The light induces a metabolic shift from glycolysis to mitochondrial activity in pro-inflammatory microglia affected by oligomeric Aβ. Thereby, the level of anti-inflammatory microglia increases. This process is accompanied by a decrease in pro-inflammatory cytokines and an activation of phagocytosis. Light exposure decreases the Aβ-induced activity of glucose-6-phosphate dehydrogenase, an enzyme that regulates the rate of the pentose phosphate pathway, which activates nicotinamide adenine dinucleotide phosphate oxidases to further produce ROS. During co-cultivation of neurons with microglia, light prevents the death of neurons, which is caused by ROS produced by Aβ-altered microglia.
Conclusions
These original data clarify reasons for how photobiomodulation protects against neurodegeneration and support the use of light for therapeutic research in the treatment of Alzheimer's disease.
The effect of UV/visible/NIR light (380/450/530/650/808/1064 nm) on ROS generation, mitochondrial activity, and viability is experimentally compared in human neuroblastoma cancer cells. The absorption of photons by mitochondrial photoacceptors in Complexes I, III, IV is in‐detail investigated by sequential blocking with selective pharmaceutical blockers. Complex I absorbs UV/blue light by heme P450, resulting in a very high rate (14 times) of ROS generation leading to cell death. Complex III absorbs green light, by cytochromes b, c1 and c, and possesses less ability for ROS production (7 times), so that only irradiation lower than 10 mW/cm2 cause an increase in cell viability. Complex IV is well‐known as the primary photoacceptor for red/NIR light. Light of 650/808 nm at 10–100 mW/cm2 generates a physiological ROS level about 20% of a basal concentration, which enhance mitochondrial activity and cell survival. While, 1064 nm light does not show any distinguished effects. Further, ROS generation induced by low‐intensity red/NIR light is compared in neurons, immune and cancer cells. Red light seems to more rapidly stimulate ROS production, mitochondrial activity, and cell survival than 808 nm. At the same time, different cell lines demonstrate slightly various rates of ROS generation, peculiar for their cellular physiology.
Fotobiyomodülasyonun Keşfi
Canlıların çevresel faktörlere, kimyasallara veya toksik maddelere
düşük dozda maruziyeti, hormesis (bifazik doz) olarak adlandırılan
canlının adaptasyon kazanma sürecini sağlamaktadır. Düşük dozlarda stres faktörlerinin teröpotik olarak kullanılması hastalığa direnç kazanma veya adaptasyonu hızlandırmakta, yüksek dozlarda fonksiyon kaybı, moleküler hasar veya apoptoz oluşabilmektedir (Kısım ve Uzunoğlu, 2012). Antik çağlardan beri insan vücudundaki hastalıkları tedavi etmek için ışık kullanılmaktadır. Lazer ışığının biyolojik alanlarda hemen her alanda uygulamaları olmasına rağmen, hücreler, dokular ve hücresel mekanizmalarda düşük yoğunluklu tedaviler için etki mekanizması, hala tartışmalı olmaya devam ediyor. 1960 yılında lazerin icadından hemen sonra Macar bir doktor olan Endre Mester (Mester ve ark.,1971) hayvanları ve insanları ışınlamak için düşük güçte kırmızı (632.8 nm) He-Ne lazer kullandı. İlk çalışmalarında lazerin yara iyileşmesini hızlandırdığını gördü, ancak doğru tedavi parametreleri kullanılmadığı için daha sonraki uygulamalarda başarı sağlanamadı. Ayrıca lazerin çalışma sistemi bilgisi olmadan, düşük güçlü lazerin verimli bir şekilde nasıl uygulanacağını karar vermek zordu.
Photobiomodulation (PBM) is now over 50 years old and has recently started to gain more widespread acceptance within the medical community. Alleviation of the side effects of cancer therapy has so far been one of the most impressive applications of PBM and the focus of this chapter. I will cover the mechanism of action and ask whether the effects of PBM on cancer cells and tumors is more likely to be positive or negative. There are some ways that PBM could actually attack the cancer either directly or indirectly, or in combination with other cytotoxic therapies. Finally, I will summarize the clinical applications of PBM against such side effects as oral mucositis, radiation dermatitis, dysphagia, hyposalivation and xerostomia, taste alterations, trismus, head and neck lymphedema, and voice and speech alterations.
Photobiomodulation of low-level laser therapy （LLLT） has favorable biological effects on periodontal tissue. We reviewed basic studies on the cytological responses of cells in periodontal tissue for LLLT by Er:YAG laser in vitro. Low-level Er:YAG laser irradiation has been reported to affect proliferation and gene expression in osteoblasts, osteocytes, fibroblasts, and periodontal ligament cells.
A gel containing the inclusion complex of quercetin and β-cyclodextrin was developed in order to verify its effects, isolated or using phonophoresis, on oxidative biomarkers after skeletal muscle injury. 30 male rats were divided into one of five groups: Control (CTRL), Muscle Injury (MI), Therapeutic Pulsed Ultrasound (TPU), Therapeutic Pulsed Ultrasound plus Quercetin (TPU plus gel-QUE) or Quercetin gel (QUE). Quercetin gel was complexed with β-Cyclodextrin (β-CD) using chromatography (HPLC). TPU and quercetin application occurred with 2, 12, 24, 48, 72, 96 hours intervals after injury. Gastrocnemius muscle was injured by mechanical trauma. Lipid peroxidation, superoxide dismutase activity, and catalase activity were assessed. The inclusion complex exhibited adequate entrapment efficiency, relative density and pH. The viscosity of the complex showed a non-Newtonian pseudoplastic behavior. Quercetin/β-cyclodextrin gel reduced lipid peroxidation, superoxide dismutase activity and catalase activity compared to muscle injury group. Similarly, phonophoresis and TPU also reduced the levels of these oxidative biomarkers. In conclusion, quercetin/β-cyclodextrin transdermal gel reduces oxidative stress biomarkers after skeletal muscle injury irrespective of using phonophoresis.
Objective: To assess whether photobiomodulation therapy (PBMT) induces angiogenesis in diabetic mice with hindlimb ischemia (HLI). Background: Patients with diabetes mellitus (DM) are at high risk of developing peripheral arterial disease (PAD) in the lower extremities. PBMT has been shown to promote angiogenesis both in vitro and in vivo and could be a treatment for DM patients with PAD. Methods: Femoral artery ligation/excision in mice was performed to induce HLI as an animal model of PAD. PBMT at a dose of 660 nm and 1.91 J/cm2 was delivered for 10 min on 5 consecutive days after the HLI surgery. Control mice received HLI only. Mice in the DM group were injected with streptozocin to induce diabetes before HLI surgery. Mice in the laser and DM+ laser groups received both HLI and PBMT, and the latter group had induced DM. After the laser treatment, lower limb blood flow was evaluated by laser Doppler. The capillary density and CD31 were analyzed by immunofluorescence staining, and protein levels of vascular endothelial growth factor (VEGF)-A, hypoxia-inducible factor-1α (HIF-1α), inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), and extracellular signal-regulated kinases (ERK) were measured by Western blotting of tissue samples. Results: Compared with the control and DM mice, the laser and DM+ laser groups had more than double the capillary density and blood perfusion rate. Levels of CD31 and VEGF-A proteins in groups that received laser were increased by 1.9- to 3.2-fold compared with groups that did not undergo laser treatment. Animals treated with PBMT exhibited significantly increased HIF-1α expression and ERK phosphorylation compared with animals that did not receive this treatment, and the amount of phospho-eNOS and iNOS increased and decreased, respectively. Conclusions: PBMT can induce therapeutic angiogenesis, indicating that low intensity laser could be a novel treatment for PAD patients.
The objective of this study was to analyze the effectiveness of phonophoresis with copaiba oil gel, in comparison to therapeutic pulsed ultrasound alone or topical application of copaiba oil gel, on oxidative stress after a traumatic muscle injury. Forty male Wistar rats were divided into five groups: control, muscle injury, therapeutic pulsed ultrasound (TPU), copaiba oil gel (CO) and TPU plus CO. TPU and CO application occurred at 2, 12, 24, 48, 72 and 96 h after injury. The gastrocnemius muscle was injured by mechanical trauma. Malondialdehyde (a lipoperoxidation marker) and superoxide dismutase and catalase (antioxidant enzymes) were assessed 98 h after muscle injury. All were elevated in the muscle injury group. There was a significant difference among treatment groups favoring TPU plus CO for reducing malondialdehyde levels, but all treatments reduced superoxide dismutase and catalase activity, with no between-groups difference. In conclusion, phonophoresis—the application of TPU plus CO—was superior to TPU or CO alone for reducing lipoperoxidation. Phonophoresis, TPU alone and CO were all effective in decreasing antioxidant enzyme activity after a traumatic skeletal muscle injury.
The promoter of the murine gene encoding inducible nitric oxide synthase (iNOS) contains an NF-kappa B site beginning 55 base pairs upstream of the TATA box, designated NF-kappa Bd. Reporter constructs containing truncated promoter regions, when transfected into macrophages, revealed that NF-kappa Bd is necessary to confer inducibility by bacterial lipopolysaccharide (LPS). Oligonucleotide probes containing NF-kappa Bd plus the downstream 9 or 47 base pairs bound proteins that rapidly appeared in the nuclei of LPS-treated macrophages. The nuclear proteins bound to both probes in an NF-kappa Bd-dependent manner, but binding was resistant to cycloheximide only for the shorter probe. The proteins binding both probes reacted with antibodies against p50 and c-rel but not RelB; those binding the shorter probe also reacted with anti-RelA (p65). Pyrrolidine dithiocarbamate, which acts as a specific inhibitor of NF-kappa B, blocked both the activation of the NF-kappa Bd-binding proteins and the production of NO in LPS-treated macrophages. Thus, activation of NF-kappa Bd/Rel is critical in the induction of iNOS by LPS. However, additional, newly synthesized proteins contribute to the NF-kappa Bd-dependent transcription factor complex on the iNOS promoter in LPS treated mouse macrophages.
This paper relates the effects caused in the muscle-tendon unit of the peritendon of the triceps surae in twenty adult male rats when submitted to trauma and xylocaine-steroid injection, trauma and xylocaine injection, and trauma only. Microscopic and biomechanic (resistance) tests of the muscle-tendon unit were obtained in five series. The first, second and third series had injection in a weekly interval basis (24 hours, 1 and 2 weeks) after the initial trauma. The fourth and fifth series (3 and 4 weeks) had no injection; microscopic and biomechanic studies showed clearly the harmful effect of xylocaine-steroid injection in the muscle-tendon unit.
There is increasing interest in the involvement of transcription factors, such as of the transcription factor NF-κB (nuclear factor-κB), in the pathogenesis of various diseases. NF-κB is involved in the control of the transcription of a variety of cellular genes that regulate the inflammatory response by the production of cytokines, chemokines, cell adhesion molecules and acute phase proteins. The involvement of NF-κB is especially of interest as it is activated by oxidative stress and its activation can be modulated by antioxidant compounds. The activation of NF-κB can be determined by the electromobility shift assay (EMSA) with a NF-κB binding-site-specific probe. EMSA can also be used on human mononuclear cells isolated from peripheral blood, which could make the assay applicable for clinical trials. The critical steps of the EMSA are discussed, addressing some pitfalls of the assay. The procedure that can be used to express NF-κB activity in human subjects is evaluated. This offers the possibility to use NF-κB as a functional biomarker of oxidative stress as illustrated by several examples of in vitro and in vivo studies.
The aim of the study was to verify in an experimental model the effects of laser therapy performed with Ga-Al-As diode lasers
(780 nm, 2500 mW) on traumatised muscles. Forty adult New Zealand male rabbits were divided into four groups (A, B, C and
D) of ten animals each. Each group of animals was further divided into two subgroups of five animals each. The animals were
submitted to muscular trauma for 7 min by clamping the posterior muscles of the left thigh under general anaesthesia. Four
days later, the rabbits in the B1, B2, C1, C2, D1 and D2 subgroups started daily laser therapy. The parameters utilised were: 150 J/cm2 energy density, 3 W, 50 Hz in group B; 250 J/cm2, 3 W, 100 Hz in group C; and 800 J/cm2, 3 W, 0 Hz (continuous output) in group D. The animals in subgroups A1 and A2 were used as untreated controls and allowed to heal spontaneously. In order to prepare samples for histological, histochemical
and histomorphometrical studies, dissection of the posterior muscle of the thigh was performed under general anaesthesia and
before sacrifice, after five days of laser therapy in the subgroups B1, C1 and D1 and after ten days of laser therapy in subgroups B2, C2 and D2. The samples of untreated subgroups A1 and A2 were subjected to the same procedure and at the same times as the corresponding laser-treated groups. The following parameters
were analysed on muscular samples: qualitative histological aspect (lactate dehydrogenase (LDH), cytochrome oxidase, acid
phosphatase and alkaline phosphatase concentration with histoenzymatic methods) and quantitative histomorphometric evaluation
of muscular damage and tissue repair. Blood samples were drawn from each subgroup before the trauma and again before sacrifice
to measure the creatine phosphokinase (CK) and LDH levels. The results obtained in the tables are shown. Analysis of the results
showed a better qualitative and quantitative healing process in traumatised muscles treated with Ga-Al-As diode laser therapy
than in spontaneously healed ones. The results obtained with laser therapy were confirmed as haematic, histoenzymatic and
histomorphometric values. According to these results, there is a positive relationship between the biostimulation properties
of the laser and the healing of traumatised muscular tissue.
1. Lipid peroxidation and hepatic fibrogenesis were investigated in 25 carbon tetrachloride-treated rats and in 25 control animals. Rats were further divided into two groups to receive either a standard diet or one supplemented with zinc. From each group, animals were killed at weeks 3 and 18 of the experiment for histological and biochemical assessments which included hepatic lipid peroxide and collagen concentrations and plasma zinc concentration as well as the hepatic activities of proline hydroxylase and collagenase.
2. Results indicated that oral zinc supplementation was associated with a decrease in lipid peroxidation (mean 51%; P<0.05), collagen deposition (mean 32%; P< 0.001) and proline hydroxylase activity (mean 30%; P<0.05) at week 18, together with an increase in collagenase activity (mean 208%; P<0.01) at week 3, in carbon tetrachloride-treated rats.
3. There was a significant direct correlation between lipid peroxidation and proline hydroxylase activity in carbon tetrachloride-treated rats (r = 0.52; P<0.01) and also a significant inverse correlation between lipid peroxidation and plasma zinc concentration in these animals (r = −0.62; P<0.001).
4. These findings are consistent with the hypothesis that hepatic lipid peroxidation plays an important role in the aetiology of hepatic fibrogenesis and that zinc mitigates the process.
Interleukin-6 (IL-6) is one of the major mediators of inflammation, and its expression is inducible by the other inflammatory
lymphokines, interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha). We demonstrate that a common IL-6 promoter
element, termed inflammatory lymphokine-responsive element (ILRE), is important for induction of IL-6 gene expression by IL-1
and TNF-alpha despite possible differences in the mechanisms of action of these lymphokines. Remarkably, the ILRE sequence,
located between -73 to -63 relative to the mRNA cap site, is highly homologous to NF-kappa B transcription factor-binding
motifs and binds an IL-1-TNF-alpha-inducible nuclear factor; the sequence specificities, binding characteristics, and subcellular
localizations of this factor are indistinguishable from those of NF-kappa B. In addition, mutations of the ILRE sequence which
impair the binding of this nuclear factor abolished the induction of IL-6 gene expression by IL-1 and TNF-alpha in vivo. These
results indicate that a nuclear factor indistinguishable from NF-kappa B is involved in the transcriptional activation of
the IL-6 gene by IL-1 and TNF-alpha.
Alveolar type II cells express a high affinity receptor for pulmonary surfactant protein A (SP-A), and the interaction of SP-A with these cells leads to inhibition of surfactant lipid secretion. We have investigated the binding of native and modified forms of SP-A to isolated rat alveolar type II cells. Native and deglycosylated forms of SP-A readily competed with 125I-SP-A for cell surface binding. Alkylation of SP-A with excess iodoacetamide yielded forms of SP-A that did not inhibit surfactant lipid secretion and did not compete with 125I-SP-A for cell surface binding. Reductive methylation of SP-A with H2CO and NaCNBH3 yielded forms of SP-A with markedly reduced receptor binding activity that also exhibited significantly reduced capacity to inhibit lipid secretion. Modification of SP-A with cyclohexanedione reversibly altered cell surface binding and the activity of SP-A as an inhibitor of lipid secretion. Two monoclonal antibodies that block the function of SP-A as an inhibitor of lipid secretion completely prevented the high affinity binding of SP-A to type II cells. A monoclonal antibody that recognizes epitopes on SP-A but failed to block the inhibition of secretion also failed to completely attenuate high affinity binding to the receptor. Concanavalin A inhibits phospholipid secretion of type II cells by a mechanism that is reversed in the presence of excess alpha-methylmannoside. Concanavalin A did not block the high affinity binding of 125I-SP-A to the receptor. Neither the high affinity binding nor the inhibitor activity of SP-A was prevented by the presence of mannose or alpha-methylmannoside. The SP-A derived from humans with alveolar proteinosis is a potent inhibitor of surfactant lipid secretion but failed to completely displace 125I-SP-A binding from type II cells. From these data we conclude that: 1) cell surface binding activity of rat SP-A is directly related to its capacity to inhibit surfactant lipid secretion; 2) monoclonal antibodies directed against SP-A can be used to map binding domains for the receptor; 3) the lectin activity of SP-A against mannose ligands does not appear to be essential for cell surface binding; 4) concanavalin A does not compete with SP-A for receptor binding; and 5) the human SP-A derived from individuals with alveolar proteinosis exhibits different binding characteristics from rat SP-A.
The polypeptides of the human erythrocyte membrane were analyzed by polyacrylamide gel electrophoresis in 1% sodium dodecyl sulfate. Six major bands (I-VI) together make up over two-thirds of the protein staining profile. Component III (mol wt 89,000) predominates in the ghost membrane; it constitutes 30% of the protein and numbers over 106 chains/ghost. Components I and II form a slow-moving doublet (approximate mol wt 250,000) containing 25% of the protein. The molar amounts of I + II, IV (mol wt 77,500), V (mol wt 41,300), and VI (mol wt 36,200) are similar, falling in the range 3.4-4.6 × 105 chains/ghost. Four bands were recognized in gels stained by the periodic acid-Schiff procedure. A broad Schiff-positive zone just behind the tracking dye corresponds to membrane lipids. Three bands of lower mobility are sialoglycoproteins. The most prominent of these has an apparent molecular weight of 83,500 and contains at least 57% of the sialic acid of ghosts. The Schiff-positive bands were not colored by protein stains. Sialidase treatment of ghosts selectively increased the mobilities of the sialoglycoproteins without affecting the protein-staining profile. Attempts to produce subunits from the large polypeptides by treatment with various denaturing agents were unsuccessful. Normally, no polypeptides of size less than 15,000 were seen in ghost electrophorograms. However, heating ghosts with low levels of sodium dodecyl sulfate and high levels of salt produced diffuse bands of low average molecular weight. This highly variable effect is attributed to degradation by proteinases. Components I, II, and V were solubilized by incubating ghosts at low ionic strength. Component VI was released by washing with buffered saline at concentrations above 0.1 M. Both elution procedures were rapid (15 min), complete, and selective; they were also conservative in that new bands were not created and the electrophorograms of released and retained material were complementary. The eluted material contained negligible sialic acid and no Schiff-positive lipids. Two classes of membrane protein were distinguished by their response to the elution procedures. Components I, II, V, and VI compose one class. They make up 30-35 % of the protein and are tenuously related to the membrane, possibly by predominantly ionic bonds. The second class, which includes components III, IV, and the sialoglycoproteins, together with various minor components, constitutes 65-70% of the protein. These polypeptides are tightly bound; their properties may reflect participation in hydrophobic protein-protein and protein-lipid interactions.
We have developed a procedure for preparing extracts from nuclei of human tissue culture cells that directs accurate transcription
initiation in vitro from class II promoters. Conditions of extraction and assay have been optimized for maximum activity using
the major late promoter of adenovirus 2. The extract also directs accurate transcription initiation from other adenovirus
promoters and cellular promoters. The extract also directs accurate transcription initiation from class III promoters (tRNA
and Ad 2 VA).
The promoter of the murine gene encoding inducible nitric oxide synthase (iNOS) contains an NF-kappa B site beginning 55 base pairs upstream of the TATA box, designated NF-kappa Bd. Reporter constructs containing truncated promoter regions, when transfected into macrophages, revealed that NF-kappa Bd is necessary to confer inducibility by bacterial lipopolysaccharide (LPS). Oligonucleotide probes containing NF-kappa Bd plus the downstream 9 or 47 base pairs bound proteins that rapidly appeared in the nuclei of LPS-treated macrophages. The nuclear proteins bound to both probes in an NF-kappa Bd-dependent manner, but binding was resistant to cycloheximide only for the shorter probe. The proteins binding both probes reacted with antibodies against p50 and c-rel but not RelB; those binding the shorter probe also reacted with anti-RelA (p65). Pyrrolidine dithiocarbamate, which acts as a specific inhibitor of NF-kappa B, blocked both the activation of the NF-kappa Bd-binding proteins and the production of NO in LPS-treated macrophages. Thus, activation of NF-kappa B/Rel is critical in the induction of iNOS by LPS. However, additional, newly synthesized proteins contribute to the NF-kappa Bd-dependent transcription factor complex on the iNOS promoter in LPS-treated mouse macrophages.
In chronic inflammatory diseases, such as asthma, rheumatoid arthritis, inflammatory bowel disease, and psoriasis, several cytokines recruit activated immune and inflammatory cells to the site of lesions, thereby amplifying and perpetuating the inflammatory state.1 These activated cells produce many other mediators of inflammation. What causes these diseases is still a mystery, but the disease process results from an interplay of genetic and environmental factors. Genes, such as those for atopy in asthma and for HLA antigens in rheumatoid arthritis and inflammatory bowel disease, may determine a patient's susceptibility to the disease and the disease's severity, but environmental factors, often unknown, . . .
The role of melatonin as an immunomodulator is well established. Recent reports showed that melatonin exerts protective effects in septic and hemorrhagic shock and in inflammation. The expression of the inducible isoform of nitric oxide synthase (iNOS) makes an important contribution to the pathophysiology of shock and inflammation. We studied, in cultured murine macrophages, the role of melatonin in the regulation of the expression of iNOS and defined the mode of melatonin's action. Our results show that melatonin, at 1 microM-1 mM, decreased the production of nitrite/nitrate (the breakdown products of NO) as well as the production of 6-keto-prostaglandin F1alpha (the major stable breakdown product of prostacyclin) in macrophages stimulated with bacterial lipopolysaccharide (10 microg/ml). We observed that melatonin reduces iNOS steady-state mRNA levels and iNOS protein expression in the same concentration range (1 microM-1 mM). Melatonin, up to 10 mM, exerted only a slight direct inhibitory effect on iNOS activity. Using iNOS promoter-luciferase constructs, we found that melatonin inhibits iNOS promoter activation. Inhibition of iNOS expression was associated with inhibition of activation of the transcription factor nuclear factor kappa B (NFkappaB). We conclude that melatonin inhibits NO production in immunostimulated macrophages mainly by inhibiting the expression of iNOS. This is due to inhibition of iNOS transcription, in part through inhibition of NFkappaB activation. Inhibition of iNOS-derived NO production by melatonin may contribute to the anti-inflammatory effects of this pineal secretory product.
Skeletal muscle is often the site of tissue injury due to trauma, disease, developmental defects or surgery. Yet, to date, no effective treatment is available to stimulate the repair of skeletal muscle. We show that the kinetics and extent of muscle regeneration in vivo after trauma are greatly enhanced following systemic administration of curcumin, a pharmacological inhibitor of the transcription factor NF-kappaB. Biochemical and histological analyses indicate an effect of curcumin after only 4 days of daily intraperitoneal injection compared with controls that require >2 wk to restore normal tissue architecture. Curcumin can act directly on cultured muscle precursor cells to stimulate both cell proliferation and differentiation under appropriate conditions. Other pharmacological and genetic inhibitors of NF-kappaB also stimulate muscle differentiation in vitro. Inhibition of NF-kappaB-mediated transcription was confirmed using reporter gene assays. We conclude that NF-kappaB exerts a role in regulating myogenesis and that modulation of NF-kappaB activity within muscle tissue is beneficial for muscle repair. The striking effects of curcumin on myogenesis suggest therapeutic applications for treating muscle injuries.
The progression of chronic renal diseases is characterized by the accumulation of extracellular matrix proteins in the glomerulus. The present experiments were designed to analyze the effect of hydrogen peroxide on the contractile and proliferative phenotypes of human mesangial cells grown on different culture substrates: plastic, collagen type I, and collagen type IV. Contraction was analyzed by measuring planar cell surface area and myosin light chain phosphorylation, whereas proliferation was studied by [(3)H]thymidine incorporation. No changes were detected in the proliferation rate of human mesangial cells grown on different culture substrates, neither under basal conditions nor in the presence of fetal calf serum or H(2)O(2). Cells grown on plastic or collagen did not contract in the presence of H(2)O(2), but cells grown on collagen I elicited a significant contraction with H(2)O(2). Platelet-activating factor induced contraction of human mesangial cells on the three culture substrates. The different contractile responses observed were not due to different degradation rates of H(2)O(2). The present experiments support the importance of extracellular matrix in the response to exogenous stimuli and point to the possibility that patients with changes in the mesangial matrix as a result of chronic renal diseases may have an increased susceptibility to the pathological actions of reactive oxygen species.
Our aim was to investigate whether the antioxidant quercetin might protect against liver injury in chronically biliary obstructed rats.
Secondary biliary cirrhosis was induced by 28 days of bile duct obstruction. Animals received quercetin at 75, 150 and 300 micromol x kg body wt(-1) x day(-1) i.p. through the experimental period or at 150 micromol x kg body wt(-1) x day(-1) i.p. for the last 2 weeks.
Bile duct obstruction resulted in a decrease in the activities of antioxidant enzymes. Liver oxidised/reduced (GSSG/GSH) glutathione ratio, hepatic and mitochondrial thiobarbituric acid reactive substances (TBARS) and collagen content were significantly increased and a marked fibrosis and bile ductular proliferation was observed. Quercetin corrected the reduction in glutathione concentration and partially prevented the increase in collagen concentration, TBARS and GSSG/GSH ratio. Treatment resulted in a significant preservation of the activities of antioxidant enzymes, a less pronounced fibrosis and a marked inhibition of bile ductular proliferation. Maximal effects were reached with the intermediate quercetin dose given for 2 or 4 weeks.
Quercetin reduces liver oxidative damage, ductular proliferation and fibrosis in biliary-obstructed rats. These effects suggest that it might be a useful agent to preserve liver function in patients with biliary obstruction.
The purpose of this study was to investigate the effects of low-power laser irradiation on wound healing in genetic diabetes.
Female C57BL/Ksj/db/db mice received 2 dorsal 1 cm full-thickness incisions and laser irradiation (830 nm, 79 mW/cm(2), 5.0 J/cm(2)/wound). Daily low-level laser therapy (LLLT) occurred over 0-4 days, 3-7 days, or nonirradiated. On sacrifice at 11 or 23 days, wounds were excised, and tensile strengths were measured and standardized.
Nontreated diabetic wound tensile strength was 0.77 +/- 0.22 g/mm(2) and 1.51 +/- 0.13 g/mm(2) at 11 and 23 days. After LLLT, over 0-4 days tensile strength was 1.15 +/- 0.14 g/mm(2) and 2.45 +/- 0.29 g/mm(2) (P = 0.0019). Higher tensile strength at 23 days occurred in the 3- to 7-day group (2.72 +/- 0.56 g/mm(2) LLLT vs. 1.51 +/- 0.13 g/mm(2) nontreated; P < or = 0.01).
Low-power laser irradiation at 830 nm significantly enhances cutaneous wound tensile strength in a murine diabetic model. Further investigation of the mechanism of LLLT in primary wound healing is warranted.
Skeletal muscle is often the site of tissue injury due to trauma, disease, developmental defects or surgery. Yet, to date, no effective treatment is available to stimulate the repair of skeletal muscle. We show that the kinetics and extent of muscle regeneration in vivo after trauma are greatly enhanced following systemic administration of curcumin, a pharmacological inhibitor of the transcription factor NF-κB. Biochemical and histological analyses indicate an effect of curcumin after only 4 days of daily intraperitoneal injection compared with controls that require >2 wk to restore normal tissue architecture. Curcumin can act directly on cultured muscle precursor cells to stimulate both cell proliferation and differentiation under appropriate conditions. Other pharmacological and genetic inhibitors of NF-κB also stimulate muscle differentiation in vitro. Inhibition of NF-κB-mediated transcription was confirmed using reporter gene assays. We conclude that NF-κB exerts a role in regulating myogenesis and that modulation of NF-κB activity within muscle tissue is beneficial for muscle repair. The striking effects of curcumin on myogenesis suggest therapeutic applications for treating muscle injuries.
Muscle strain injuries occur to predictable muscles at consistent locations during expected sporting maneuvers when a muscle is stretched and then activated, particularly during high intensity bursts of activity. More than 30% of the injuries seen in the clinician's office are injuries to skeletal muscle. The typical location of the injury is just proximal to the distal muscle tendon junction regardless of strain rate or architecture of the muscle. After the injury, the muscle is weaker, continues to weaken, then recovers during the next week. An inflammatory response is seen in the following 1 to 2 days. By the seventh day, fibrous tissue replaces the inflammatory reaction and a scar forms. When a muscle is stretched, its tension still is reduced making the healing muscle more susceptible to a repeat injury. Viscoelastic properties of muscle also can help explain how muscle can be protected against strain injury. A 1degrees C increase in muscle temperature (warm-up) increases the muscle length to failure and a fatigued muscle is more susceptible to strain injury. It probably is impossible to prevent muscle strain injury; however, preventive measures can make muscle more resistant to these stretch-induced injuries.
NF-kappaB/Rel transcription factor family participates in diverse biological. processes including embryo,, development, hematopoiesis, immune regulation, as well as neuronal functions. In this review, the NF-kappaB/Rel signal transduction pathways and their important roles in the regulation of immune system will be discussed. NF-kappaB/Rel members execute distinct functions in multiple immune cell types via the regulation of target genes essential for cell proliferation, survival, effector functions, cell trafficking and communication, as well as the formation of lymphoid architecture. Consequently, proper activation of NF-1cB/ Rel during immune responses to allergens, auto-antigens, allo-antigens, and pathogenic infection is crucial for the integrity of host innate and adaptive immunity.
Background
Muscle strain injuries are extremely common in sports medicine. Muscle healing often is hindered by scar tissue formation after injury.
Hypothesis
Suramin can prevent scar tissue formation and improve muscle healing after injury because of its ability to antagonize transforming growth factor– β1, a fibrotic cytokine.
Study Design
Controlled laboratory study.
Materials and Methods
In vitro, muscle-derived fibroblasts (a potential cell source of muscle fibrosis) were incubated with suramin and/or transforming growth factor– β1; a cell growth curve was obtained. In vivo, mouse gastrocnemius muscles were strain injured. Suramin or sham/control intramuscular injections were performed after injury at various time points. Mice were sacrificed at various time points after injury, and skeletal muscle tissue was evaluated by using histological and physiological tests. Statistical analysis was performed by using analysis of variance and Fisher tests.
Results
Suramin decreased the stimulating effect of transforming growth factor– β1 on the growth of muscle-derived fibroblasts in vitro. Significantly less fibrous scar formation was observed in suramin-treated muscles than in sham-injected muscles. The fast-twitch and tetanus strength of suramin-treated muscles was also significantly greater relative to that of control muscles.
Conclusions
Suramin blocked the stimulatory effect of transforming growth factor– β1 on muscle-derived fibroblasts in vitro. Suramin also reduced fibrous scar formation in muscle and enhanced muscle strength in strain-injured skeletal muscle.
Clinical Relevance
These results may facilitate the development of strategies to enhance muscle healing after injury.
Background: Given the recent interest in light-emitting diode (LED) photomodulation and minimally invasive nonablative laser therapies, it is timely to investigate reports that low-level laser therapy (LLLT) may have utility in wound healing. Objectives: To critically evaluate reported in vitro models and in vivo animal and human studies and to assess the qualitative and quantitative sufficiency of evidence for the efficacy of LLLT in promoting wound healing. Method: Literature review, 1965 to 2003. Results: In examining the effects of LLLT on cell cultures in vitro, some articles report an increase in cell proliferation and collagen production using specific and somewhat arbitrary laser settings with the helium neon (HeNe) and gallium arsenide lasers, but none of the available studies address the mechanism, whether photothermal, photochemical, or photomechanical, whereby LLLT may be exerting its effect. Some studies, especially those using HeNe lasers, report improvements in surgical wound healing in a rodent model; however, these results have not been duplicated in animals such as pigs, which have skin that more closely resembles that of humans. In humans, beneficial effects on superficial wound healing found in small case series have not been replicated in larger studies. Conclusion: To better understand the utility of LLLT in cutaneous wound healing, good clinical studies that correlate cellular effects and biologic processes are needed. Future studies should be well-controlled investigations with rational selection of lasers and treatment parameters. In the absence of such studies, the literature does not appear to support widespread use of LLLT in wound healing at this time. Although applications of high-energy (10–100 W) lasers are well established with significant supportive literature and widespread use, conflicting studies in the literature have limited low-level laser therapy (LLLT) use in the United States to investigational use only. Yet LLLT is used clinically in many other areas, including Canada, Europe, and Asia, for the treatment of various neurologic, chiropractic, dental, and dermatologic disorders. To understand this discrepancy, it is useful to review the studies on LLLT that have, to date, precluded Food and Drug Administration approval of many such technologies in the United States. The fundamental question is whether there is sufficient evidence to support the use of LLLT.
There have been many reports on the applications of low reactive level laser (LLL) therapy for pain attenuation or pain removal. Our group has reported previously on the effects of in vitro irradiation of LLL particularly on the phagocytic activity of human neutrophils, using luminol-dependent chemiluminescence (LmCL) for measurement of reactive oxygen species (ROS) production from human neutrophils. But the mechanisms of the attenuation of phagocytic activity of neutrophils by LLL irradiation is not yet full understood. In this study, we used luminol-dependent and lucigenin-dependent chemiluminescence (LgCL) for detection of affected ROS producing process of human neutrophils by LLL irradiation, Two soluble action stimuli, N-formyl-Met-Leu-Phe (fMLP) and phorbol myristate acetate (PMA) were used to avoid the possible influence of lag-time from recognition to uptake of particles at the ROS production. In case of using fMLP as a stimulus, the maximum luminescence intensity of LmCL was increased but LgCL luminescence was decreased by LLL irradiation. When PMA was used as a stimulus, the times to reach the maximum luminescence intensity of LmCL and LgCL were shortened by LLL irradiation but there was no effect on the maximum luminescence intensity of both. These results suggest that LLL irradiation enhances the ROS production activity of human neutrophils by the activation of the superoxide converting system, the active element in which is mainly myeloperoxidase. LLL irradiation enabled a more rapid activation of the superoxide production system, NADPH-oxidase.
NF-κB/Rel transcription factor family participates in diverse biological processes including embryo development, hematopoiesis, immune regulation, as well as neuronal functions. In this review, the NF-κB/Rel signal transduction pathways and their important roles in the regulation of immune system will be discussed. NF- κB/Rel members execute distinct functions in multiple immune cell types via the regulation of target genes essential for cell proliferation, survival, effector functions, cell trafficking and communication, as well as the formation of lymphoid architecture. Consequently, proper activation of NF- κB/ Rel during immune responses to allergens, auto-antigens, allo-antigens, and pathogenic infection is crucial for the integrity of host innate and adaptive immunity.
Many forms of treatment are utilized by physiotherapists for the treatment of soft tissue injuries. One of these is the use of low powered laser (LPLT). The purpose of this study was to determine the effects of LPLT (lj/cm2, daily 10) on acute blunt trauma to muscles in controlled animal experiments. A reproducible model of single acute blunt trauma to the lower leg muscles of anaesthetized male rats (n=28) was used. The level of contractile protein content and collagenous protein content were determined 12 days post-trauma in control, injured, laser-control and laser treated animals. Our data demonstrated an overall decrease in the levels of contractile protein content, in the various groups, which were not statistically different (p>0.05), and an overall significant increase in the levels of collagenous protein content (p<0.005). It was concluded that the LPLT protocol used for the recovery of injured muscle was not of significant benefit during the time period employed in this study (day 3 to day 12 post-trauma) following acute blunt trauma. The data confirmed a decrease in the levels of contractile proteins and an increase in the levels of collagenous proteins in muscle following injury.
Objective: The intracellular pathway and the regulation of inducible nitric oxide synthase (iNOS) expression in skeletal muscle is incompletely understood. In vitro studies, using different cell types, suggest that inflammatory cytokines are potential triggers to induce iNOS expression. Methods: To analyze intracellular pathways leading to iNOS induction, rat skeletal myoblasts were incubated with inflammatory cytokines and assessed for iNOS expression by Western blot and Griess reaction. To confirm the in vitro findings, local cytokine levels were determined in skeletal muscle biopsies of patients with chronic heart failure (CHF) and correlated with iNOS expression. Results: Nitrite accumulation in the myoblast culture supernatant or iNOS protein in the cell pellet was significantly increased after incubation with IL-1β in combination with γ-IFN. Priming experiments revealed that γ-IFN elevated the expression of IL-1β receptor mRNA, whereby IL-1β was able to induce iNOS expression. The cytokine-mediated iNOS induction was significantly reduced by blocking ERK1/ERK2 activation and completely abolished by the inhibition of NFκB. In skeletal muscle biopsies of CHF patients the local content of IL-1β was significantly increased as compared to healthy controls. Furthermore, a linear correlation between IL-1β content and iNOS expression in the skeletal muscle was detected. Conclusions: These data demonstrate that IL-1β, together with the priming effect of γ-IFN, induces iNOS expression in skeletal muscle via activation of ERK1/ERK2 and NFκB.
Muscle injury presents a challenging problem in traumatology and is frequently encountered in sports medicine. The injury can occur via a variety of mechanisms, ranging from direct mechanical deformation (as in contusions, lacerations, and strain) to indirect causes (such as ischemia and neurological damage). Injured muscle usually undergoes a process of degeneration and regeneration. The injured muscle fibers first undergo necrosis, during which the damaged myofibers are removed by macrophages. New muscle fibers regenerate within the connective tissue framework of the damaged muscle. Even though muscles retain their ability to regenerate after injury, the healing process is very slow and often leads to incomplete functional recovery. We, along with others, have observed that injured muscle promptly initiates the process of healing; however, it is often inefficient and hindered by fibrosis (ie, scar tissue formation). This review is intended to increase the reader's understanding of the muscle healing process and will cover the events that occur after muscle injury including: (1) the pathological processes of degeneration and inflammation, (2) the biological repair process of muscle regeneration, and (3) the development of muscle fibrosis during the repair process. We will also discuss potential biological approaches to enhance muscle regeneration and prevent muscle fibrosis, which can eventually be used to improve muscle healing after injuries. This chapter should further our understanding of the muscle healing process and may help to develop novel and innovative therapies to promote efficient muscle healing for complete functional recovery after injuries.
Background Given the recent interest in light-emitting diode (LED) photomodulation and minimally invasive nonablative laser therapies, it is timely to investigate reports that low-level laser therapy (LLLT) may have utility in wound healing.Objectives To critically evaluate reported in vitro models and in vivo animal and human studies and to assess the qualitative and quantitative sufficiency of evidence for the efficacy of LLLT in promoting wound healing.Method Literature review, 1965 to 2003.Results In examining the effects of LLLT on cell cultures in vitro, some articles report an increase in cell proliferation and collagen production using specific and somewhat arbitrary laser settings with the helium neon (HeNe) and gallium arsenide lasers, but none of the available studies address the mechanism, whether photothermal, photochemical, or photomechanical, whereby LLLT may be exerting its effect. Some studies, especially those using HeNe lasers, report improvements in surgical wound healing in a rodent model; however, these results have not been duplicated in animals such as pigs, which have skin that more closely resembles that of humans. In humans, beneficial effects on superficial wound healing found in small case series have not been replicated in larger studies.Conclusion To better understand the utility of LLLT in cutaneous wound healing, good clinical studies that correlate cellular effects and biologic processes are needed. Future studies should be well-controlled investigations with rational selection of lasers and treatment parameters. In the absence of such studies, the literature does not appear to support widespread use of LLLT in wound healing at this time. Although applications of high-energy (10–100 W) lasers are well established with significant supportive literature and widespread use, conflicting studies in the literature have limited low-level laser therapy (LLLT) use in the United States to investigational use only. Yet LLLT is used clinically in many other areas, including Canada, Europe, and Asia, for the treatment of various neurologic, chiropractic, dental, and dermatologic disorders. To understand this discrepancy, it is useful to review the studies on LLLT that have, to date, precluded Food and Drug Administration approval of many such technologies in the United States. The fundamental question is whether there is sufficient evidence to support the use of LLLT.WILLIAM POSTEN, MD, DAVID A. WRONE, MD, JEFFREY S. DOVER, MD, FRCPC, KENNETH A. ARNDT, MD, SIRUNYA SILAPUNT, MD, AND MURAD ALAM, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS.
Low energy laser photostimulation at certain wavelengths can enhance tissue repair by releasing growth factors from fibroblasts and stimulate the healing process. This study was designed to evaluate the influence of laser photostimulation on collagen production in experimentally tenotomized and repaired rabbit Achilles tendons.
A total of 24 male New Zealand rabbits, ages 10-12 weeks, were used. Following tenotomy and repair, the surgical hind limbs of the rabbits were immobilized in customized polyurethane casts. The experimental animals were treated with a 632.8 nm He:Ne laser daily at 1.0 J cm(-2) for 14 days. Control animals were sham treated with the laser head. On the fifth day after repair, the casts were removed to allow the animals to bear weight on the lower extremity. The animals were euthanized on the 15th postoperative day, then, the Achilles tendons were excised, processed and analyzed.
Biochemical analyses of the tendons revealed a 26% increase in collagen concentration with laser photostimulation indicating a more rapid healing process in treated tendons compared to controls. Sequential extractions of collagen from regenerating tissues revealed that the laser photostimulated tendons had 32% and 33% greater concentrations of neutral salt soluble collagen and insoluble collagen, respectively, than control tendons suggesting an accelerated production of collagen with laser photostimulation. A significant decrease (9%) in pepsin soluble collagen was observed in laser-treated tendons compared to controls. There were no statistically significant differences recorded in the concentrations of hydroxypyridinium crosslinks and acid soluble collagen between treated and control tendons.
This study of laser photostimulation on tendon healing in rabbits suggests that such therapy facilitates collagen production in a manner that enhances tendon healing.
Publisher Summary This chapter discusses microsomal lipid peroxidation. Lipid peroxidation is a complex process known to occur in both plants and animals. It involves the formation and propagation of lipid radicals, the uptake of oxygen, a rearrangement of the double bonds in unsaturated lipids, and the eventual destruction of membrane lipids, producing a variety of breakdown products, including alcohols, ketones, aldehydes, and ethers. Biological membranes are often rich in unsaturated fatty acids and bathed in an oxygen-rich, metal-containing fluid. Lipid peroxidation begins with the abstraction of a hydrogen atom from an unsaturated fatty acid, resulting in the formation of a lipid radical. The formation of lipid endoperoxides in unsaturated fatty acids containing at least 3 methylene interrupted double bonds can lead to the formation of malondialdehyde as a breakdown product. Nonenzymic peroxidation of microsomal membranes also occurs and is probably mediated in part by endogenous hemoproteins and transition metals. The direct measurement of lipid hydroperoxides has an advantage over the thiobarbituric acid assay in that it permits a more accurate comparison of lipid peroxide levels in dissimilar lipid membranes.
The absorption spectrum of human fibroblast monolayers showed several absorption peaks, among them one at a wave-length of 630 nm. Cultures of these fibroblasts were subjected to He-Ne laser (632.8 nm) irradiation of various energy doses by varying power density and exposure time. On three consecutive days the cell monolayers were irradiated for periods between 0.5 and 10 min. Laser power varied from 0.55 to 5.98 mW. Both cell number and collagen type I production were determined for each irradiation condition within one experiment. Results show that laser power below 2.91 mW could enhance cell proliferation (as determined by cell counting), whereas higher laser power (5.98 mW) had no effect. Stimulatory effects were most pronounced at irradiation times between 0.5 and 2 min. Collagen type I production (as determined by an ELISA) was affected in the opposite direction to cell proliferation: when the cell proliferation was increased, collagen type I production was decreased. From these experiments it is clear that exposure time and power density determine the effects of laser irradiation. Both stimulation and inhibition of the observed cell properties can be obtained with the same laser on the same cells.
Low-power He-Ne laser irradiation causes a well-defined and energy dependent cell destruction of in vitro cultured cell lines sensitized by hematoporphyrin derivative (HPD). The mechanism of this photosensitization was studied by measuring with polarization microscopic, scanning electron microscopic, and electron-spin-resonance (ESR) spectroscopic parameters. The cell damage caused by photosensitization and laser irradiation seems to be a complex process, however the biological membranes seem to be one of the primary targets. The energy of laser light causes rotation and resonance changes of macromolecules and the water molecules, resulting in an increased structural order of the submembraneous components in the living cells, detectable microscopically. During the photosensitization process, the red (630 nm) He-Ne laser light, during a one-photon energy activation, causes excitation of hematoporphyrin molecules to their triplet state. The excitation of HPD molecules results in a multi-step, free-radical generating effect, measured by ESR spectroscopy and studied by the ultrastructural changes of membrane organization and cell shape. Similar effects could be observed on in vitro lipid-water liposome membranes.
Using variable-length deletion constructs of the 5'-flanking region of the human interleukin-6 (IL-6) gene linked to the chloramphenicol
acetyltransferase gene, we showed that the region from positions -109 to -50 mediated the bulk of the response to tumor necrosis
factor (TNF) or interleukin-1 (IL-1), while it was less responsive to forskolin. DNA mobility shift assays and DNase I footprinting
analysis identified a nuclear protein from TNF- or IL-1-treated fibroblasts that bound to a region comprising a kappa B-like
element located between positions -72 and -63 on the IL-6 gene. On the basis of these and other experiments, we conclude that
TNF and IL-1 apparently activate IL-6 gene expression by closely related mechanisms involving activation of a NF-kappa B-like
factor, whereas the pathway of IL-6 induction by forskolin is, in part, different.
Macrophages are a source of many important mediators of wound repair. It was the purpose of this study to see if light could stimulate the release of these mediators.
In this study an established macrophage-like cell line (U-937) was used. The cells were exposed in culture to the following wavelengths of light: 660 nm, 820 nm, 870 nm, and 880 nm. The 820-nm source was coherent and polarised, and the others were non-coherent. Twelve hours after exposure the macrophage supernatant was removed and placed on 3T3 fibroblast cultures. Fibroblast proliferation was assessed over a 5-day period.
The results showed that 660-nm, 820-nm, and 870-nm wavelengths encouraged the macrophages to release factors that stimulated fibroblast proliferation above the control levels, whereas the 880-nm wavelength either inhibited the release of these factors or encouraged the release of some inhibitory factors of fibroblast proliferation.
These results suggest that light at certain wavelengths may be a useful therapeutic agent by providing a means of either stimulating or inhibiting fibroblast proliferation where necessary. At certain wavelengths coherence is not essential.
The effects of helium-neon laser (HNL) on activity, absorption spectra, and ESR signals of superoxide dismutase (SOD; E Cul.15.1.1) from bovine erythrocytes in acid medium were investigated. It was found that incubation during 2 hours at pH 5.9 led to inactivation of the enzyme. The subsequent illumination of SOD by HNL brought about the enzyme reactivation. Both absorption and ESR spectra were changed after incubation at pH 5.9 and restored after laser irradiation. In a model system, copper-histidine complex, absorption maximum was shifted from 632-633 nm at pH 5.8 to 639-640 nm at pH 8.5-9.0. The similar shift of the maximum was observed after illumination by HNL at pH 5.8. It may be postulated that the photoreactivation of SOD consists essentially in deprotonation of His-61 residue in the enzyme active site and subsequent recovery of imidasol bridge between copper and zinc which had been destroyed at low pH. Since many other enzymes possess similar histidine-copper structures in their active sites, one may expect diverse effects of red (laser) light on the enzyme activity. Heme-containing enzyme, catalase was also found to be photoreactivated by HNL after inactivation at pH 6.0.
Recent evidence suggests that low-energy lasers, such as an He-Ne laser, might stimulate wound healing. In this review we are summarizing our recent observations indicating that low-energy lasers enhance collagen gene expression both in skin fibroblast cultures in vitro, as well as in animal models of wound healing in vivo.
The method described in this communication is sensitive and allows direct determination of the specific radioactivities of proline and hydroxyproline in collagen and in noncollagenous proteins, when proline-14C is used as a precursor. It is also useful in determining free proline in tissues and sera, as well as proline and hydroxyproline in protein hydrolysates.
Lipid peroxidation and the antioxidant system were studied in 36 patients with surgical diseases of the gastrointestinal tract. Time course of these parameters was studied in the postoperative period. Differences in lipid peroxidation during standard endovascular laser therapy were revealed, caused by the initial status of the antioxidant system. Combined use of endovascular laser irradiation of the blood and antioxidant therapy helped rule out the undesirable induction of free-radical processes in these patients.
These studies investigate the role of transforming growth factor-beta 1, a potent inhibitor of epithelial cell proliferation and stimulator of extracellular matrix biosynthesis, during intrahepatic bile duct hyperplasia and biliary fibrosis. These pathogenic responses were induced in rats by common bile duct ligation. Bile duct cell replication, measured by the bromodeoxyuridine labeling index, was significantly increased 24 hr after common bile duct ligation. This response diminished to baseline by 1 wk. Liver collagen content, determined by quantification of hydroxyproline, was increased significantly after 1 wk of common bile duct ligation, and by 4 wk was increased by a factor of 4. Immunohistochemistry revealed low levels of TGF-beta 1 in normal intrahepatic bile duct epithelium. In contrast, the bile duct epithelium in bile duct-ligated rats stained strongly positive for transforming growth factor-beta 1 at 1 and 4 wk after ligation. These results suggest that transforming growth factor-beta 1 may play a role in both the termination of the bile duct epithelial cell proliferative response and the induction of fibrogenesis after common bile duct ligation. In addition, the mannose 6-phosphate/insulin-like growth factor II receptor was up-regulated in hyperplastic bile duct epithelium 1 and 4 wk after ligation. Because the mannose 6-phosphate/insulin-like growth factor-II receptor has been shown to facilitate the proteolytic activation of transforming growth factor-beta 1, these results suggest that the bile duct epithelium may also be involved in the activation of transforming growth factor-beta 1.
In this study the effect of CO2 laser on spinal epidural fibrosis was examined in 24 guinea pigs which were divided into two groups. The first group was the control group, the second one the CO2 laser group. All animals had laminectomies at 3 levels. Re-exploration was performed three months after the laminectomy. In the second group the same procedure was performed but at the end of the re-exploration, CO2 laser irradiation of the epidural fibrotic tissue was done. The wounds in both groups were closed again. Four months later all animals were sacrificed. For verification and quantification of scar formation (postoperative fibrosis) light microscopic examinations and determination of hydroxyproline were done, using Bergman's spectrophotometric method. The differences which were observed between the two groups were statistically significant (U : 134, P < 0.05). This study demonstrates the reducing effect of CO2 laser irradiation on epidural scar formation. The findings encourage its use as an alternative method of prevention of epidural fibrosis after spinal surgery.
Various chronic disease processes are characterized by progressive accumulation of connective tissue under-going fibrotic degeneration. Evidence of oxidative reactions is often associated with fibrogenesis occurring in liver, lung, arteries, and nervous system. Moreover, an increasing bulk of experimental and clinical data supports a contributory role of oxidative stress in the pathogenesis of this kind of disease. Indeed, many etiological agents of fibrogenesis stimulate free radical reactions either directly or through inflammatory stimuli. Free radicals, as well as products of their reaction with biomolecules, appear to modulate the activity of the two cellular types mainly involved in the process, namely phagocytes and extracellular matrix-producing cells. Lipid peroxidation and certain lipid peroxidation products induce genetic overexpression of fibrogenic cytokines, the key molecules in the pathomechanisms of fibrosis, as well as increased transcription and synthesis of collagen. Both these events can be downregulated, at least in experimental models, by the use of antioxidants. The effect of oxidative stress on cytokine gene expression appears to be an important mechanism by which it promotes connective tissue deposition.
Nitric oxide (NO) is synthesized in wounds, but its exact role and cellular source are not known. Wound fibroblasts (WF) are phenotypically characterized by increased collagen synthesis and contractility. We hypothesized that WF may be also phenotypically altered during wound healing to synthesize NO. WF were isolated from polyvinyl alcohol sponges implanted in male Lewis rats and harvested 10 days later. Proliferation in response to 10% fetal bovine serum was assessed by [3H]thymidine incorporation in a microculture system. A fibroblast-populated collagen lattice was used for assaying contractility. Collagen synthesis was determined by measuring the collagenase-sensitive fraction of protein-incorporated [3H]proline. Fibroblasts were incubated in the presence or the absence of 0.5 mM S-methyl-isothio-uronium or 0.5 mM N-monomethyl-L-arginine, both competitive inhibitors of NO synthase. WF spontaneously synthesize and release NO (4.60 +/- 0.29 nmol nitrite/microg DNA/48 h). Normal dermal fibroblasts do not synthesize NO. WF NO synthesis was limited to the first and second passages postharvest and was inhibitable by S-methyl-isothio-uronium (96%) and N-monomethyl-L-arginine (84%). In vivo iNOS expression by WF was confirmed by in situ hybridization and immunohistochemistry. Inhibition of endogenous NO synthesis had no effect on fibroblast proliferation. However, fibroblast-mediated collagen contraction was enhanced (p < 0.01), and collagen synthesis was significantly decreased (p < 0.05) by inhibiting NO synthase. The data show that WF are phenotypically altered during the healing process to synthesize NO, which, in turn, regulates their collagen synthetic and contractile activities.
The free radical nitric oxide (NO) has emerged in recent years as a fundamental signaling molecule for the maintenance of homeostasis, as well as a potent cytotoxic effector involved in the pathogenesis of a wide range of human diseases. Although this paradoxical fate has generated confusion, separating the biological actions of NO on the basis of its physiologic chemistry provides a conceptual framework which helps to distinguish between the beneficial and toxic consequences of NO, and to envision potential therapeutic strategies for the future. Under normal conditions, NO produced in low concentration acts as a messenger and cytoprotective (antioxidant) factor, via direct interactions with transition metals and other free radicals. Alternatively, when the circumstances allow the formation of substantial amounts of NO and modify the cellular microenvironment (formation of the superoxide radical), the chemistry of NO will turn into indirect effects consecutive to the formation of dinitrogen trioxide and peroxynitrite. These "reactive nitrogen species" will, in turn, mediate both oxidative and nitrosative stresses, which form the basis of the cytotoxicity generally attributed to NO, relevant to the pathophysiology of inflammation, circulatory shock, and ischemia-reperfusion injury.
Muscle injury triggers a sequence of events that begin with a host inflammatory response that is followed by muscle fiber regeneration and new collagen synthesis. The inflammatory response involves at least three types of cells, including neutrophils, ED1+ macrophages, and ED2+ macrophages. A host of growth factors and cytokines appear to play a role in the inflammatory process and repair of the damaged tissue. Satellite cells play an integral role in normal development of skeletal muscle by providing a source for postmitotic myonuclei. In addition, the satellite cell is essential to the repair of injured muscle by serving as a source of myoblasts for fiber regeneration. At the same time muscle fiber regeneration is occurring, there is expression of types I and III collagen that under certain circumstances can lead to scarring and fibrosis. Current studies of treatment of muscle injury often incorporate investigations of basic principles of injury and repair together with clinical experience and principles in an effort to coordinate basic science and outcome studies.
Oxidative stress has traditionally been viewed as a stochastic process of cell damage resulting from aerobic metabolism, and antioxidants have been viewed simply as free radical scavengers. Only recently has it been recognized that reactive oxygen species (ROS) are widely used as second messengers to propagate proinflammatory or growth-stimulatory signals. With this knowledge has come the corollary realization that oxidative stress and chronic inflammation are related, perhaps inseparable phenomena. New pharmacological strategies aimed at supplementing antioxidant defense systems while antagonizing redox-sensitive signal transduction may allow improved clinical management of chronic inflammatory or degenerative conditions, including Alzheimer's disease. Introduction of antioxidant therapies into mainstream medicine is possible and promising, but will require significant advances in basic cell biology, pharmacology, and clinical bioanalysis.
To evaluate the possibility of oxygen radical damage in the skin after He-Ne laser irradiation according to dose intensity and time.
The He-Ne laser (lambda = 632.8, 10 mW) was used on the skin of mice with 1, 3, and 5 joule (J/cm2) dose rates for 1, 5, and 7 days in each case, and the results were compared with normal and anesthetic nonirradiated skins. The efficacy was determined by the formation of thiobarbituric acid-reactive substances (TBARS) in a 10-minute period and expressed as a concentration of malondialdehyde (MDA) from the lipid peroxidation of epidermal tissue, and total superoxide dismutases (SODs) and catalase activities, correlated with histologic biopsies.
Data from epidermal SODs, catalase activity and the degree of lipid peroxidation at low-power radiation showed that repeated exposure had led to the induction of free radical damage and of epidermal changes as confirmed by microscopic study. The application of the He-Ne laser at 1, 3, and 5 J intensity for 5 days caused a gradual increase in the SODs and catalase activities, while the levels of TBARS were slightly decreased in the mouse epidermis. However, these patterns were reversed after 3 and 5 J irradiations for 5 and 7 days laser treatment. Furthermore, microscopic examinations revealed that the laser-irradiated skin changed the release of stratum granule from epidermis to hair follicle, and produced blood vessel thrombosis of the dermal capillary plexus.
The presence of lipid peroxidation in the hairless mouse skin after exposure to He-Ne laser energy intensity of over 3 J for over 5 days was demonstrated. This lipid peroxidation could have been generated from oxygen free radicals. The histologic and oxidative enzymatic correlations on lipid peroxidation in the skin have provided a better understanding of He-Ne laser therapy-tissue interactions. It is possible to take advantage of these findings to evaluate pathologic skin conditions and effective laser dosage more efficiently.
Following tissue injury, adequate inflammatory vascular responses are essential for subsequent tissue repair. The aims of this study were to investigate the role of reactive oxygen species (ROS, generated at the injury site) in modulating the inflammatory response under acute- and chronic-injury conditions. The effect of age and the implications of this modulation for tissue repair was investigated. Using laser Doppler flowmetry, inflammatory vascular responses were monitored in the base of vacuum-induced blisters in the hind footpad of anesthetized rats (65 mg/kg Nembutal). Inflammation was amplified by superfusion of substance P (SP) over the blister base. The inflammatory response was examined in acute blisters induced on either naïve skin (acute-injury model) or on skin innervated by a chronically injured nerve (chronic-injury model). Furthermore, the acute-injury model was examined during early and late phases, 0 and 5 h after blister induction, respectively. The involvement of ROS was assessed by either combined superfusion of the antioxidants: superoxide dismutase and catalase over the blister base in acute-injury, or intramuscular injection of tirilazad in chronically injured rats. The results showed that antioxidant treatment had no effect on the response during early and late phases of acute inflammation in young rats. However in old rats, the vascular response was significantly attenuated (60%) or significantly increased (40%) during the early and late phases of acute inflammation, respectively. Under chronic-injury conditions, antioxidant treatment significantly enhanced the response in both young and old rats. We then examined the effect of antioxidant, tirilazad, on the healing of a full thickness thermal injury induced in the intrascapular region (using a CO(2) laser) of the rat. Following burn injury, tirilazad was injected around the wound site starting on day 1 (early treatment) or day 6 (late treatment). Tirilazad had opposing actions on wound closure with early and late treatments delaying (24.6 +/- 0.6 d) or accelerating (14.2 +/- 0.3 d) wound closure compared with the group of aged controls (20.3 +/- 0.8 d). The results suggest that ROS have a paradoxical role exerting either a positive or negative effect on the inflammatory response with age. We contend that the role of ROS in modulating inflammation should be considered when designing treatment protocols to accelerate tissue repair.
Nuclear factor kappaB (NF-kappaB) is thought to play an important role in the expression of genes expressed in response to ischemia/reperfusion (I/R) injury. In this report, the activation of NF-kappaB in rat skeletal muscle during reperfusion following a 4-h ischemic period was studied. NF-kappaB activation displayed a biphasic pattern, showing peak activities from 30 min to 3 h postperfusion and 6 h to 16 h postperfusion, with a decline to baseline binding activity levels between 3 h and 6 h. Inhibition of NF-kappaB activation was investigated using proline dithiocarbamate (Pro-DTC). NF-kappaB binding activity during reperfusion was significantly reduced by intravenous administration of Pro-DTC. Additionally, Pro-DTC resulted in decreased muscle edema and neutrophil activity, with an increased percentage of muscle survival compared with vehicle controls. These results demonstrate that NF-kappaB is activated during reperfusion in a biphasic manner and that the regulation of the initial phase of NF-kappaB activation affords physiological protection against a severe ischemic stress. Selective inhibition of NF-kappaB during early reperfusion may therefore be a therapeutic intervention for I/R injury.