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Low-Intensity Laser Irradiation Improves the Mitochondrial Dysfunction of C2C12 Induced by Electrical Stimulation
Abstract
We investigated the effects of electrical stimulation and low-intensity laser (LIL) energy on the mitochondrial function of cultured C2C12 myotubes in order to find a dosage that could be used to improve the function of mitochondria, and then rehabilitate exercise-induced damage and fatigue. Background Data: Many other studies in the past demonstrated that LIL had a cytoprotective effect, and a recent study also found that LIL could reduce muscular fatigue during tetanic contractions in rats.
Cultured C2C12 myotubes were subjected to electrical stimulation or/and LIL irradiation at various intensities. Reactive oxygen species (ROS) were detected with a fluorescent probe (DCFH-DA) and mitochondrial function was assessed with an MTT assay.
The results showed that electrical stimulation at 20 ms, 5 Hz, and 45 V for 75 min can induce mitochondrial dysfunction in cultured C2C12 myotubes. Electrical stimulation-induced mitochondrial dysfunction was improved, but degeneration occurred with LIL at doses of 0.33-8.22 and 11.22-14.16 J/cm2, respectively, and these changes were markedly increased with LIL at 0.33 and 1.34 J/cm2, respectively.
We conclude that treatment of myotubes with the proper dosage of LIL irradiation significantly diminished production of ROS and restored mitochondrial function, and this may provide a foundation for the use of photobiomodulation to treat exercise-induced mitochondrial dysfunction or skeletal muscular fatigue.
... Interleaved NMES exploits the previously-described spatial differences in the way NMES over the muscle and nerve recruit MUs. Interleaved NMES reduces fatigue by ~30-40% compared to over-the-muscle or nerve alone during light tibialis anterior contractions (15% maximum voluntary contraction [MVC]) (17), with a similar effect observed in contractions up to at least 30% MVC (18). As contraction strength increases further, however, the -overlap‖ of MUs recruited by the muscle and nerve sites increases (10), and will theoretically eventually negate the advantage of the interleaved approach. ...
... Lopes-Martins et al. (15) observed reduced post-NMES muscle fatigue in isolated rat muscles exposed to phototherapy. Subsequent studies support these findings in frog (16) and mouse (17) muscles as well as in cell cultures (18). In humans, Leal-Junior et al. (19) found that individuals performed more elbow flexion-extension repetitions before task failure immediately after LLLT than placebo. ...
... Animal models have also shown laser interventions to decrease oxidative stress (58,59). Xu et al. (18), for example, verified that laser treatment significantly decreased ROS production and restored mitochondrial function. In addition to these functional changes at the cell membrane and cytosolic organelles, Manteifel et al. (60) observed giant mitochondria in human lymphocytes after laser irradiation that could produce greater ATP levels. ...
Neuromuscular electrical stimulation (NMES) applied to skeletal muscles is an effective rehabilitation and exercise training modality. However, the relatively low muscle force and rapid muscle fatigue induced by NMES limits the stimulus provided to the neuromuscular system, and subsequent adaptations. We hypothesise that adaptations to NMES will be enhanced by the use of specific stimulation protocols and adjuvant interventions.
... The results of these previous studies (Lopes-Martins et al. 2006;Vieira et al. 2006) encouraged other researchers to develop more experimental studies in order to identify other interactions between LLLT and muscle tissue subjected to different physical exercises as well as the mechanisms of action of LLLT to reduce damage and muscle fatigue (de Almeida et al. 2011;Liu et al. 2009;Sussai et al. 2010;Xu et al. 2008). Liu et al. (2009) trained rats on a treadmill in the declined plane (-16 slope) at a speed of 16 m/min until the animals' exhaustion. ...
... LLLT and LEDT have been used to combat ROS and RNS produced during physical exercise (Baroni et al. 2010a,b;de Almeida et al. 2012;Leal Junior et al. 2009a,b, 2011Liu et al. 2009;Sussai et al. 2010;Xu et al. 2008) for improvement in mitochondrial function that contributes to the reduction of muscle fatigue and the increase in muscle performance. LLLT and LEDT use CCO as the primary photoacceptor, and the main effects of this interaction are increased ATP synthesis and increased mitochondrial function (Hayworth et al. 2010;Huang et al. 2009;Karu 2010;Silveira et al. 2009;Vladimirov, Osipov, and Klebanov 2004;Xu et al. 2008). ...
... LLLT and LEDT have been used to combat ROS and RNS produced during physical exercise (Baroni et al. 2010a,b;de Almeida et al. 2012;Leal Junior et al. 2009a,b, 2011Liu et al. 2009;Sussai et al. 2010;Xu et al. 2008) for improvement in mitochondrial function that contributes to the reduction of muscle fatigue and the increase in muscle performance. LLLT and LEDT use CCO as the primary photoacceptor, and the main effects of this interaction are increased ATP synthesis and increased mitochondrial function (Hayworth et al. 2010;Huang et al. 2009;Karu 2010;Silveira et al. 2009;Vladimirov, Osipov, and Klebanov 2004;Xu et al. 2008). The relationship between light, mitochondria, ROS, and RNS involves the reduction of ROS and the photodissociation of NO-CCO, contributing to the restoration of oxygen consumption and ATP synthesis in mitochondria (Huang et al. 2009;Vladimirov, Osipov, and Klebanov 2004). ...
... More recent studies have reported LLLT effects on mitochondria in different types of cells (5)(6)(7)(8)(9). In neural cells LLLT seems to also increase MMP, protect against oxidative stress (5) and increase ATP synthesis in intact cells (without stressor agents) (6). ...
... In mitochondria from fibroblast cells without stressor agents, LLLT also increased ATP synthesis and mitochondrial complex IV activity in a dose-dependent manner (7). In myotubes from C2C12 cells, LLLT could modulate the production of reactive oxygen species (ROS) and mitochondrial function in a dosedependent manner in intact cells or in cells stressed by electrical stimulation (9). ...
... Next, these cells were distributed equally into 30 wells (approximately 5. After plating C2C12 cells were cultured for 9 days in culture medium (DMEM) containing 2% heat-inactivated horse serum (Sigma-Aldrich) in a humidified incubator at 37°C and 5% CO 2 to induce cell differentiation into myotubes, as described in a previous study (9). At the 10 th day, LEDT-24 h group received LEDT. ...
Low level laser (light) therapy has been used before exercise to increase muscle performance in both experimental animals and in humans. However uncertainty exists concerning the optimum time to apply the light before exercise. The mechanism of action is thought to be stimulation of mitochondrial respiration in muscles, and to increase adenosine triphosphate (ATP) needed to perform exercise. The goal of this study was to investigate the time course of the increases in mitochondrial membrane potential (MMP) and ATP in myotubes formed from C2C12 mouse muscle cells and exposed to light-emitting diode therapy (LEDT). LEDT employed a cluster of LEDs with 20 red (630 ± 10 nm, 25 mW) and 20 near-infrared (850 ± 10 nm, 50 mW) delivering 28 mW/cm(2) for 90 sec (2.5 J/cm(2) ) with analysis at 5 min, 3 h, 6 h and 24 h post-LEDT. LEDT-6h had the highest MMP, followed by LEDT-3h, LEDT-24h, LEDT-5min and Control with significant differences. The same order (6h>3h>24h>5min>Control) was found for ATP with significant differences. A good correlation was found (r=0.89) between MMP and ATP. These data suggest an optimum time window of 3-6 h for LEDT stimulate muscle cells. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
... Xu et al. (2003) proposed that LLL treatment may be useful in preventing muscular fatigue since cytochromes in the respiratory chain can absorb laser irradiation at specific wavelengths, which then enhances electron transfer and reduces free radical formation leading to greater ATP production (Assis et al. 2013). This hypothesis was supported in subsequent studies by Xu et al. (2008) which indicated that low dose laser treatment significantly inhibited ROS production in C2Cl2 cells, showing an hormetic J-shaped dose response. Likewise, over the same treatment range (0.33-8.22 J/cm 2 ) mitochondrial function (MTT assay) was enhanced (Fig. 16). ...
... While the above studies of Xu et al. (2008) concerned muscle fatigue, LLL also enhanced muscle repair in numerous experimental settings (Lopez-Martins et al. 2006). As was the case with ATP production, hormetic effects have also been reported for muscle repair using C2Cl2 cells during cell viability assays as well as with biomarkers of muscle injury (myoD and Pax 7) (Brunnelli et al. 2014;Trajano et al. 2016a, b). ...
Sarcopenia is a significant public health and medical concern confronting the elderly. Considerable research is being directed to identify ways in which the onset and severity of sarcopenia may be delayed/minimized. This paper provides a detailed identification and assessment of hormetic dose responses in animal model muscle stem cells, with particular emphasis on cell proliferation, differentiation, and enhancing resilience to inflammatory stresses and how this information may be useful in preventing sarcopenia. Hormetic dose responses were observed following administration of a broad range of agents, including dietary supplements (e.g., resveratrol), pharmaceuticals (e.g., dexamethasone), endogenous ligands (e.g., tumor necrosis factor α), environmental contaminants (e.g., cadmium) and physical agents (e.g., low level laser). The paper assesses both putative mechanisms of hormetic responses in muscle stem cells, and potential therapeutic implications and application(s) of hormetic frameworks for slowing muscle loss and reduced functionality during the aging process.
... Studies have demonstrated a beneficial interaction between PBMT and the production of CK, with a reduction in the release of this marker of muscle damage when laser is administered prior to high-intensity physical activity (17) . This positive response is explained by the theory that PBMT is capable of improving the function of cellular mitochondria (18) . PBMT promotes an interaction between light and the target tissue through the stimulation of COX, which is a mitochondrial enzyme that plays an important role in the electron transport chain and consequently promotes an improvement in cell respiration and the production of energy in the form of adenosine triphosphate (4,5,19) . ...
... In a study conducted in a controlled environment, a beneficial interaction between PBMT and CK production was found, with a reduction in the release of this marker of muscle damage when PBMT was administered prior to high-intensity physical activity (22) . This positive response is explained by the theory that PBMT is capable of improving the function of cellular mitochondria (18) . In a recent systematic review and meta-analysis, Leal-Junior et al. (20) analyzed 13 articles and concluded that PBMT with LLLT and LEDT is more beneficial when administered prior to physical activity, as it preserves the muscle tissue and accelerates post-exercise recovery time. ...
Background: Photobiomodulation with low-level laser therapy (LLLT) has been widely used in clinical practice for diverse purposes, such as modulation of the inflammatory process, acceleration of the tissue repair process, pain relief and the enhancement of post-exercise recovery. Studies have demonstrated a beneficial interaction between photobiomodulation and the production of creatine kinase, with a reduction in the release of this marker of muscle damage when laser and/or LEDs is administered prior to high-intensity physical activity. Objective: The aim of the proposed study is to determine the influence of pre-exercise phototherapy on post-exercise muscle recovery. Methods: A randomized, cross-over, sham-controlled, double-blind, clinical trial is proposed. The participants will be healthy professional soccer players aged 15 to 20 years from the same team with a body mass index within the ideal range (20 to 25 kg/m2 ) and no history of lower limb musculoskeletal injuries or surgery or back surgery in the previous six months. The athletes will be allocated to two groups based on the previously calculated sample size and will be blinded to allocation. Creatine kinase will be measured and the subjective perception of fatigue will be determined for each participant. The volunteers will then be randomly allocated to Group A, which will receive active phototherapy, and Group B, which will receive sham phototherapy. The athletes will undergo reevaluations immediately after as well as 48 hours after a football match. The data will be submitted to statistical analysis and the level of significance will be set to 5%. This study is registered with Clinical Trials under protocol number: NCT03416998.
... 7 In previous researches and systematic reviews, laser therapy applied before a bout of resistance exercise provided ergogenic effects to skeletal muscle by improving physical performance 8,9 ; likewise, LLLT performed before exercise reduces accumulation in serum lactate and creatine kinase, inhibits inflammation, and accelerates muscle recovery between exercise sessions. [10][11][12][13][14] However, these studies were applied on subjects without OA. The application of LLLT on knee OA patients with quadriceps weakness or atrophy has been less discussed, and few studies have investigated the recovery of muscle strength after quadriceps muscle atrophy in knee OA status. ...
... The physiological characteristics of LLLT include enhancement of microcirculation, stimulation of mitochondrial respiratory chain to ATP synthesis. 11,33,34 In skeletal muscles with single bout of LLLT irradiation, a burst of ATP production results from stimulated cytochrome c-oxidase in respiratory chains and up-regulation of mitochondrial activity, which facilitate power generation of muscle. 35 People with knee OA problems, stronger quadriceps help knee joint stability, shock absorption, and reduction of ground reaction forces to knee during gait cycle by means of better mechanical alignment, and they further provide positive effect on functional scale, knee joint pain as consequence. ...
Low‐level laser therapy (LLLT) applying on knee osteoarthritis (OA) patients has shown positive outcomes in analgesic effect and functional recovery. However, few studies applied such therapy on large area of quadriceps muscle in these patients. The aim of this study was to evaluate immediate effect of multi‐focal LLLT on quadriceps of knee OA patients in pain and functional performance. Fifty‐one participants with knee OA were enrolled and evaluated before (T1) and immediately after intervention (T2) by knee joint pain in numeric rating scale (NRS), walking speed, timed five‐chair stands, and quadriceps strength by isokinetic dynamometer. Intervention with two multi‐focal Gallium‐Aluminum‐Arsenide laser devices, each device with 36 laser diodes (wavelength 808 ± 10 nm, continuous, mean power 50 mW, 30 minutes), applied simultaneously over bilateral quadriceps with a total dose of 180 J for each thigh. The multi‐focal LLLT significantly improved knee joint pain as measured by the NRS (54% reduction), timed five‐chair stands, and walking speed (P < .05). Knee extensor strength also increased in terms of peak torque and force of concentric and eccentric contraction as measured by isokinetic dynamometer (P < .05). In conclusion, single‐session multi‐focal LLLT on quadriceps in knee OA patients has immediate beneficial effect on knee pain reduction, quadriceps strengthening and functional performance recovery. Long‐term effect requires further investigation. Multi‐focal LLLT on quadriceps might serve as an alternative non‐invasive treatment option in these patients.
... Neste estudo, as culturas de miotubos foram continuamente irradiadas, por 600 s, com um laser de 810 nm em densidades de energia de 0,33-14,16 J/cm 2 . Os autores [35] relataram que densidades de energia de 0,33-8,22 J/cm 2 não causam nenhum dano para a função mitocondrial das células, enquanto que doses de 11,22-14,16 J/cm 2 são deletérias à função celular. ...
... Os resultados de nosso estudo não puderam ser comparados com os relatados por Xu et al. [35], pois utilizaram um comprimento de onda diferente (810nm) e relataram apenas as densidades de energia e tempo de irradiação. Além disso, eles induziram a diferenciação dos mioblastos C2C12, avaliando os efeitos do laser sobre miotubos. ...
Os efeitos da laserterapia de baixa potência estão diretamente relacionados aos parâmetros dosimétricos e ao tipo de laser utilizado. O objetivo do presente estudo foi avaliar o efeito de diferentes doses de irradiação dos lasers de GaAlAs e de InGaAlP sobre a proliferação de mioblastos cultivados em situação de carência nutricional (modelo de mimetização de injúria muscular). Os mioblastos C2C12 cultivados em meio defi ciente em nutrientes foram irradiados com laser de baixa potência de GaAlAs (660 nm) e InGaAlP (780 nm) com densidades de energia de 1,3, 2,5, 3,8 e 5 J/cm2 e 1,3, 2,5, 5 e 6,3 J/cm2, respectivamente. A proliferação celular foi avaliada 48 horas após a irradiação por meio da mensuração da atividade mitocondrial e do ensaio de cristal violeta. Não houve diferença signifi cativa na proliferação celular entre as culturas irradiadas e culturas de controle para qualquer um dos parâmetros. Mais estudos são necessários para determinar os parâmetros ideais da laserterapia na bioestimulação de mioblastos.Palavras-chave: mioblastos, laser, proliferação celular.
... Nevertheless, experimental approaches have already observed structural and functional responses supporting oxidative metabolism enhancement, such as increased mitochondrial density, size and membrane potential, increased oxidative enzyme activities, blood lactate disappearance and phosphocreatine shuttle, improvement of oxidative stress deleterious parameters, and increased microcirculation with hyperemia at the point of light application [2,[4][5][6]. ...
... This study also demonstrated positive responses of the previous LED application in the blood lactate disappearance capacity; these effects could be due the improvement in microcirculation [6,29] and also because of a decreased lactate production with prior application of light by modifications on oxidative capacity through enzymatic, mitochondrial, and systemic changes, facilitating the resynthesis of ATP by the alactic pathway [20,21,29]. Although there was no difference between conditions for LA peak , LED condition presented higher removal capacity compared to PLA, with significantly lower values of LA 13-min and LA 15-min . ...
This study aimed to investigate the effect of prior LED sessions on the responses of cardiorespiratory parameters during the running incremental step test. Twenty-six healthy, physically active, young men, aged between 20 and 30 years, took part in this study. Participants performed two incremental load tests after placebo (PLA) and light-emitting diode application (LED), and had their gas exchange, heart rate (HR), blood lactate, and rating of perceived exertion (RPE) monitored during all tests. The PLA and LED conditions were compared using the dependent Student t test with significance set at 5%. The T test showed higher maximum oxygen uptake (VO2max) (PLA = 47.2 ± 5.7; LED = 48.0 ± 5.4 ml kg⁻¹ min⁻¹, trivial effect size), peak velocity (Vpeak) (PLA = 13.4 ± 1.2; LED = 13.6 ± 1.2 km h⁻¹, trivial effect size), and lower maximum HR (PLA = 195.3 ± 3.4; LED = 193.3 ± 3.9 b min⁻¹, moderate effect size) for LED compared to PLA conditions. Furthermore, submaximal values of HR and RPE were lower, and submaximal VO2 values were higher when LED sessions prior to the incremental step test were applied. A positive response of the previous LED application in the blood lactate disappearance was also demonstrated, especially 13 and 15 min after the test. It is concluded that LED sessions prior to exercise modify cardiorespiratory response by affecting running tolerance during the incremental step test, metabolite clearance, and RPE. Therefore, LED could be used as a prior exercise strategy to modulate oxidative response acutely in targeted muscle and enhance exercise tolerance.
... [18][19][20][21] PBMT consists in applying a non-ionised form of light, which includes laser (light amplification by stimulated emission of radiation), light-emitting diodes and other lights with a broader spectrum ranging from visible to infrared. 22 Recent evidence [23][24][25][26][27][28] suggests that PBMT triggers positive physiological effects, such as increased microcirculation, 23 increased ATP synthesis 24 25 stimulation of the mitochondrial respiratory chain, 24 25 stimulation of mitochondrial function 26 and factors that may influence the metabolism of various pathologies. In addition, there is evidence that PBMT reduces the release of both reactive oxygen species) and creatine kinase activity and also increases the production of antioxidants and heat shock proteins. ...
... [18][19][20][21] PBMT consists in applying a non-ionised form of light, which includes laser (light amplification by stimulated emission of radiation), light-emitting diodes and other lights with a broader spectrum ranging from visible to infrared. 22 Recent evidence [23][24][25][26][27][28] suggests that PBMT triggers positive physiological effects, such as increased microcirculation, 23 increased ATP synthesis 24 25 stimulation of the mitochondrial respiratory chain, 24 25 stimulation of mitochondrial function 26 and factors that may influence the metabolism of various pathologies. In addition, there is evidence that PBMT reduces the release of both reactive oxygen species) and creatine kinase activity and also increases the production of antioxidants and heat shock proteins. ...
Introduction
Low back pain (LBP) is one of the largest and most frequent public health problems worldwide. Photobiomodulation therapy (PBMT) is a frequently used non-pharmacological therapy for the treatment of musculoskeletal disorders. However, there is little high-quality scientific evidence that demonstrates the effectiveness of PBMT in the treatment of patients with chronic LBP in the short, medium and long term. Therefore, the objective of this clinical trial is to evaluate the effects of PBMT in patients with chronic non-specific LBP in the short, medium and long term.
Methods and analyses
This is a prospectively registered, two-arm randomised placebo-controlled trial with blinded patients, assessors and treatment providers. One hundred and forty-eight patients with chronic non-specific LBP will be recruited. Treatment sessions will be provided three times a week for 4 weeks (totaling 12 sessions) with patients receiving either placebo or active PBMT. For ethical reasons, all patients, regardless of treatment allocation, will also receive an information booklet based on ‘The Back Book’. Clinical outcomes will be measured at baseline, at the end of treatment, as well as 3, 6 and 12 months after randomisation. The primary outcomes will be pain intensity and disability measured after 12 sessions of treatment. The secondary outcomes will be pain intensity and disability measured at 3, 6 and 12 months after randomisation, in addition to specific disability and global perceived effect in all time points.
Ethics and dissemination
The study was approved by the Research Ethics Committee of Universidade Cidade de São Paulo. The results will be disseminated through scientific publications and presentations at national and international scientific meetings.
Trial registration number
NCT03089424.
... [18][19][20][21] PBMT consists in applying a non-ionised form of light, which includes laser (light amplification by stimulated emission of radiation), light-emitting diodes and other lights with a broader spectrum ranging from visible to infrared. 22 Recent evidence [23][24][25][26][27][28] suggests that PBMT triggers positive physiological effects, such as increased microcirculation, 23 increased ATP synthesis 24 25 stimulation of the mitochondrial respiratory chain, 24 25 stimulation of mitochondrial function 26 and factors that may influence the metabolism of various pathologies. In addition, there is evidence that PBMT reduces the release of both reactive oxygen species) and creatine kinase activity and also increases the production of antioxidants and heat shock proteins. ...
... [18][19][20][21] PBMT consists in applying a non-ionised form of light, which includes laser (light amplification by stimulated emission of radiation), light-emitting diodes and other lights with a broader spectrum ranging from visible to infrared. 22 Recent evidence [23][24][25][26][27][28] suggests that PBMT triggers positive physiological effects, such as increased microcirculation, 23 increased ATP synthesis 24 25 stimulation of the mitochondrial respiratory chain, 24 25 stimulation of mitochondrial function 26 and factors that may influence the metabolism of various pathologies. In addition, there is evidence that PBMT reduces the release of both reactive oxygen species) and creatine kinase activity and also increases the production of antioxidants and heat shock proteins. ...
... This correlation was not observed in trained individuals, suggesting a more prominent role of aerobic energy production in fatigue resistance for untrained subjects during intense intermittent exercise (19). Considering PBMT's potential to enhance mitochondrial membrane potential and ATP synthesis in C2C12 myotubes (20), as well as its demonstrated ability to increase oxygen availability in healthy young participants (21), investigating the effects of PBMT alone or preceded by a warmup on YYIR1 performance in amateur players would be intriguing. ...
We investigated whether the application of photobiomodulation therapy (PBMT) immediately after a standardized warm-up (WU + PBMT) or traditional PBMT (no pre-warming) would influence performance in intermittent testing and intensity variables. In a counterbalanced randomized crossover design, twelve female futsal players (mean age: 23.9 ± 3.8 years) attended four sessions. Each session involved either a standardized warm-up or maintaining seated rest for five minutes. Subsequently, PBMT or placebo (with the PBMT device turned off) was applied, followed by the YoYo Intermittent Recovery Level 1 test (YYIR1) during which we assessed heart rate, rating of perceived exertion, and blood lactate levels. The performance in YYIIR1 was superior ( p = 0.02) in the WU + PBMT condition (440.0 ± 59.0 m) compared to the WU + Placebo (353.3 ± 94.7 m), and placebo alone (no warm-up) (325.0 ± 67.2 m). We conclude that a combination of a specific warm-up before PBMT application improves high-intensity intermittent performance in amateur female futsal players without affecting intensity variables.
... It works similar to photosynthesis; the correct wavelengths and power of light at certain intensities for an appropriate period of time can increase ATP production and cell membrane alterations could lead to permeability changes and second Mitochondrial Correction: A New Therapeutic Paradigm for Cancer and Degenerative Diseases VOLUME 33.4 messenger activity resulting in functional changes (Ferraresi et al., 2015;Xu, Zhao, Liu & Pan, 2008;Momenzadeh et al., 2015;Huang et al., 2012). ...
... LLLT is known to enhance mitochondrial ATP generation. This, in turn, is also correlated to DROS production (de Freitas & Hamblin, 2016;Sommer et al., 2015;Xu et al., 2008). Photobiomodulation was shown to enhance mitochondrial TMP anad ATP synthesis in auditory cell lines (Chang et al., 2019). ...
In this second half of our treatise on oxygenic photosynthesis, we provide support for the murburn model of the light reaction of photosynthesis and ratify key predictions made in the first part. Molecular docking and visualization of various ligands of quinones/quinols (and their derivatives) with PSII/Cytochrome b6f complexes did not support chartered 2e-transport role of quinols. A broad variety of herbicides did not show any affinity/binding-based rationales for inhibition of photosynthesis. We substantiate the proposal that disubstituted phenolics (perceived as protonophores/uncouplers or affinitybased
inhibitors in the classical purview) serve as interfacial modulators of diffusible reactive (oxygen) species or DR(O)S. The DRS-based murburn model is evidenced by the identification of multiple ADP binding sites on the extra-membraneous projection of protein complexes and structure/distribution of the photo/redox catalysts. With a panoramic comparison of the redox metabolic machinery across diverse organellar/cellular systems, we highlight the ubiquitous one-electron murburn facets (cofactors of porphyrin, flavin, FeS, other metal centers and photo/redox active pigments) that enable a facile harnessing of the utility of DRS. In the summative analyses, it is demonstrated that the murburn model of light reaction explains the structures of membrane supercomplexes recently observed in thylakoids and also accounts for several photodynamic experimental observations and evolutionary considerations. In
toto, the work provides a new orientation and impetus to photosynthesis research.
... The light emitted by these is supposedly absorbed by chromophores inside the cells, and thereby eliciting photophysical and photochemical events in biological tissue. 6 PBMT acts mainly on mitochondria, by improving the synthesis of adenosine triphosphate 8 and attenuating the deleterious effects of reactive oxygen species, 9 and may thereby reduce muscle damage and speed up the muscle recovery process. 10 These possible mechanisms have been linked to changes in levels of biochemical muscle damage markers (e.g., creatine kinase [CK]) and muscle function loss. ...
ABSTRACT
Background: Photobiomodulation therapy (PBMT) and Creatine (Cr) intake have been used in conjunction with heavy training, but little is known about their possible effects during a long-term training program.
Objective: We wanted to assess long-term use of PBMT and Cr in an exercise training program.
Methods: Twenty-five male Wistar rats weighing ~300 g were randomly allocated to one of five groups: A non-training control group, a training group, a training group receiving Cr, a training group receiving PBMT, and a training group receiving both PBMT and Cr. The training program consisted of 12 weeks of daily swimming training. PBMT was delivered in 6 points with a laser device (808 nm, 100 mW, 30 s per point of irradiation, 3 J, 75 J/cm2).
Results: All training groups showed significantly higher peak force and longer time to 50% decay of force, and lower creatine kinase (CK) levels than the non-training control group, thus confirming the benefit of the training program. In all outcomes related to muscle performance, the groups receiving PBMT with or without Cr supplement, performed significantly better (p<0.05) peak force and time of force decay during an electrical stimulation protocol than all the other groups. In addition, CK levels were also significantly lower for the PBMT groups when compared to the other groups.
Conclusions: We conclude that PBMT alone or in conjunction with Cr supplement at during a 12-week training program, resulted in significantly better muscle performance and lower levels of CK, a biochemical marker of muscle damage.
Key words: laser irradiation, endurance training, ergogenic aids, muscle performance, muscle damage.
... Isolated irradiation of mitochondria induces changes in mitochondrial transcription and translation, increasing cascade reactions and several respiratory chain components (e.g., cytochromes, cytochrome oxidase, and flavin dehydrogenase) [6] . PBM seems to have physiological effects, including increasing microcirculation [7] , enhancing ATP synthesis, and stimulating the mitochondrial respiratory chain [8] and mitochondrial function [9] , that may influence soft tissue metabolism in several pathologies. In addition, PBM seems to reduce the release of reactive oxygen species and increase the activity of creatine kinase (CK) and hexokinase, as well as antioxidant production [10] . ...
The purpose of this study was to investigate the effect of different doses of photobiomodulation (PBM) on mitochondrial respiratory complexes and oxidative cellular energy metabolic enzymes in the mitochondria of brain, muscle, and C6 glioma cells after different time intervals. C6 cells were irradiated with an AlGaInP laser at 10, 30, and 60 J/cm2 for 20, 60, and 120 s, respectively. After irradiation, the cells were maintained in serum-free Dulbecco's Modified Eagle's medium for 24 h, and biochemical measurements were made subsequently. Mitochondrial suspensions from adult rat skeletal muscles/brains were irradiated with an AlGaInP laser at the abovementioned doses. In one group, the reaction was stopped 5 min after irradiation and in the other 60 min after irradiation. Both the C6 cells that received the doses of 10 and 30 J/cm² showed increased complex I activity; the cells that were irradiated at 30 J/cm2 showed increased hexokinase activity. Five minutes after the introduction of PBM of the muscle mitochondria (at 30 and 60 J/cm2), the activity of complex I increased, while the activity of complex IV increased only at 60 J/cm2. One hour after the laser session, complex II activity increased in the cells treated with 10 and 60 J/cm²; however, complex IV activity showed an increase in all PBM groups. In brain mitochondria, 5 min after irradiation only the activity of complex IV increased in all PBM groups. One hour after the laser session, complex II activity increased at 60 J/cm2, and complex IV activity increased for all PBM groups when compared to controls. PBM could increase the activity of respiratory chain complexes in an apparently dose- and time-dependent manner.
... It works similar to photosynthesis; the correct wavelengths and power of light at certain intensities for an appropriate period of time can increase ATP production and cell membrane alterations could lead to permeability changes and second messenger activity resulting in functional changes (110)(111)(112)(113). ...
... It works similar to photosynthesis; the correct wavelengths and power of light at certain intensities for an appropriate period of time can increase ATP production and cell membrane alterations could lead to permeability changes and second messenger activity resulting in functional changes (110)(111)(112)(113). ...
... It works similar to photosynthesis; the correct wavelengths and power of light at certain intensities for an appropriate period of time can increase ATP production and cell membrane alterations could lead to permeability changes and second Mitochondrial Correction: A New Therapeutic Paradigm for Cancer and Degenerative Diseases VOLUME 33.4 messenger activity resulting in functional changes (Ferraresi et al., 2015;Xu, Zhao, Liu & Pan, 2008;Momenzadeh et al., 2015;Huang et al., 2012). ...
Mitochondrial dysfunction has been identified as one of the principal causes of bioenergetic decline. Although there is no single silver bullet or an exact combination of substances or supplements that will unfailingly resuscitate all aspects of failing mitochondria, it has been reported that a number of nutrients, supplements and prescription substances may alleviate or restore many aspects of mitochondrial failure.
Combinations of these, acting on multiple targets, may normalize and/or improve mitochondrial function, increase cellular and systemic energy production, alleviate mitochondrial- related disease, and delay age-related decline in many
organs and systems of the body. The rise in the incidence of cancer and deaths from cancer not only parallels the rise in the development and use of toxic chemicals and materials in the environment, but also toxins in our food and water supplies and pharmaceuticals. The rise in cancer incidence and deaths is thought to be directly caused by such toxic ingestion and the body’s increasing inability to cope with the toxic overload of xenobiotics that profoundly affects the mitochondria. It is conceivable that combinations of various mitochondrial enhancers/resuscitators, acting on various portions of the mitochondrial energy production pathway will have complementary/additive effects and decrease the cancer incidence and death rates. Here we have proposed a combination of diet, exercise and supplements containing a mixture of nutrients mentioned herein to significantly enhance mitochondrial function to help restore oxidative respiration to a level of favoring malignant cell re-differentiation or to at least restore apoptotic mechanisms since the intrinsic apoptotic pathway in cells is regulated largely by functional mitochondria. When restoring mitochondrial function, we may reverse aerobic glycolysis,
inhibit cancer cell growth and possibly, reverse malignancy. Scientific support for the use of vitamin-based and cofactor-based mitochondrial therapies is accumulating. This
Mitochondrial Correction (Mitochondrial Rescue, Mitochondrial repair) approach is intended to promote critical enzymatic reactions, reduce putative sequelae of excess free
radicals, and scavenge toxic metabolic molecules, which tend to accumulate in mitochondrial diseases. Some supplements also may act as alternative energy fuels or may bypass biochemical blocks within the respiratory chain. We believe this concept can have an important repercussion in the treatment of degenerative diseases.
... An improvement of mitochondrial function and increase in ATP synthesis within the mitochondria is seen following PBMT application. 22,23 Photobiomodulation therapy has also been shown to reduce circulating reactive oxygen species (ROS) by stimulating an increase in antioxidants and nitric oxide release. 24 "Photobiomodulation Therapy is More Effective than Cryotherapy for Skeletal Muscle Recovery: A Critically Appraised Topic" by Fisher SR, Rigby JH, Mettler JA, McCurdy KW Journal of Sport Rehabilitation © 2018 Human Kinetics, Inc. ...
Clinical Scenario: Cryotherapy is one of the most commonly used modalities for post-exercise muscle recovery despite inconsistencies in the literature validating its effectiveness. With the need to find a more effective modality, photobiomodulation therapy (PBMT) has gained popularity because of recent research demonstrating its ability to accelerate the muscle recovery process. Focused Clinical Question: Is PBMT more effective than cryotherapy at reducing recovery time and decreasing delayed onset muscle soreness (DOMS) after strenuous exercise? Summary of Key Findings: Three moderate- to high quality double-blinded, randomized placebo-controlled trials and two low- to moderate quality translational studies performed on rats were included in this CAT. All 5 studies supported the use of PBMT over cryotherapy as a treatment for post-exercise muscle recovery following exercise. PBMT was superior in reducing creatine kinase, inflammation markers, and blood lactate compared to cryotherapy following strenuous/high intensity aerobic or strength muscular exercise. PBMT was also shown to improve post-exercise muscle performance and function more than cryotherapy. Clinical Bottom Line: There is moderate evidence to suggest the use of PBMT over cryotherapy post-exercise to enhance muscle recovery in trained and untrained athletes. Shorter recovery times and increased muscle performance can be seen 24 to 96 hours following PBMT application. Strength of Recommendation: Based on consistent findings from all 5 studies, there is grade B evidence to support the use of PBMT over cryotherapy for more effective post-exercise recovery of skeletal muscle performance.
... 24 This is known as photobiostimulation. 25 The application of narrow-band light in tissues may stimulate or inhibit both the chemical and physiological functions of cells, whereas other mechanisms include promoting anti-inflammatory effects, 17 increasing the antioxidant capacity, 18 and improving the mitochondrial function. 19 It is suggested that a low-intensity eccentric exercise (10%) not only is effective in providing protection against muscle damage after submaximal eccentric contraction exercise (40%), 4 but also provides protection against Max-EEC. In addition, another study has also reported that the protective effect of 10% EEC was the same at 2 and 7 days and lasted for 2 weeks. ...
Background/objective
Previous studies have already reported an independent effect of light-load eccentric exercise (10% eccentric exercise contraction [EEC]) and low-level laser therapy (LLLT) as a protective measure against more strenuous eccentric exercise. However, the difference between these two interventions is largely unknown. Therefore, the present study aimed to compare the preconditioning effect of 10% EEC vs. LLLT on subjective, physiological, and biochemical markers of muscle damage in elbow flexors in collegiate men.
Methods
All 36 enrolled subjects were randomly assigned to either 10% EEC or LLLT group. Subjects in 10% EEC group performed 30 repetitions of an eccentric exercise with 10% maximal voluntary contraction strength 2 days prior to maximal eccentric exercise bout, whereas subjects in LLLT group were given LLLT. All the indirect markers of muscle damage were measured pre-exercise and at 24, 48, and 72 hours after the exercise-induced muscle damage protocol.
Results
The muscle soreness was reduced in both groups (p = 0.024); however, soreness was attenuated more in LLLT group at 48 hours (33.5 vs. 42.7, p = 0.004). There was no significant difference between the effect of 10% EEC and LLLT groups on other markers of muscle damage like a maximum voluntary isometric contraction (p = 0.47), range of motion (p = 0.16), upper arm circumference (p = 0.70), creatine kinase (p = 0.42), and lactate dehydrogenase (p = 0.08). Within-group analysis showed both interventions provided similar protection over time.
Conclusion
This study indicated that light-load eccentric exercise confers similar protective effect against subsequent maximal eccentric exercise as LLLT. Both the treatments could be used reciprocally based on the patient preference, costs, and feasibility of the equipment.
... Furthermore, AlGhamdi et al. demonstrated that LLLT is useful in enhancing the proliferation rate of cell lines [26]. LLLT alters photoreceptor functions and subsequent cellular signaling and cellular functions [27]. Five hypotheses describe the primary reactions after laser light absorption, namely, the single-oxygen hypothesis, redox property alteration hypothesis, nitric oxide hypothesis, transient local heating hypothesis, and superoxide anion hypothesis [28]. ...
Objectives:
Chronic nonspecific lower back pain (LBP) is a common disease. Insufficient data is currently available to conclusively confirm the analgesic effects of laser acupuncture on LBP. This study evaluated the effectiveness of laser acupuncture plus Chinese cupping in LBP treatment.
Methods:
Patients with chronic nonspecific LBP were enrolled for a randomized controlled trial and assigned to the laser acupuncture group (laser acupuncture plus Chinese cupping) and control group (sham laser plus Chinese cupping). Laser acupuncture (808 nm; 40 mW; 20 Hz; 15 J/cm(2)) and Chinese cupping were applied on the Weizhong (BL40) and Ashi acupoints for 5 consecutive days. Plasma cortisol levels were assessed before and after the 5-day treatment session. The visual analog scale (VAS) scores were recorded at baseline and throughout the 5-day treatment session.
Results:
After the treatment session, the plasma cortisol levels and VAS scores decreased significantly in both groups. In the laser acupuncture group, the VAS scores decreased significantly on days 4 and 5, and an enhanced reduction in VAS scores was observed.
Conclusion:
Laser acupuncture plus Chinese cupping at the Weizhong (BL40) and Ashi acupoints effectively reduced pain and inflammation in chronic nonspecific LBP. This therapy could be a suitable option for LBP treatment in clinical settings.
... Subsequent studies supported these findings in frogs, 9 mice, 10 and cell cultures. 11 In humans, Leal-Junior et al 12 were the pioneers to show enhanced exercise performance in humans through LLLT, further supported by studies assessing muscle fatigue and exercise recovery with LLLT and/or LEDT before performing isoinertial exercise, [12][13][14][15][16] isometric exercise, [17][18][19] isokinetic exercise, 20,21 cycling exercise, [22][23][24][25] and treadmill running. [26][27][28] These studies found positive effects of LLLT and/or LEDT prior to exercise on performance and/or recovery. ...
Evidence indicates that low-level laser therapy (LLLT) minimizes fatigue effects on muscle performance. However, the ideal
LLLT dosage to improve athletes’ performance during sports activities such as cycling is still unclear. Therefore, the goal of this
study was to investigate the effects of different LLLT dosages on cyclists’ performance in time-to-exhaustion tests. In addition,
the effects of LLLT on the frequency content of the EMG signals to assess fatigue mechanisms were examined. Twenty male
competitive cyclists participated in a crossover, randomized, double-blind, placebo-controlled trial. They performed an
incremental cycling test to exhaustion (on day 1) followed by 4 time-to-exhaustion tests (on days 2–5) at their individual
maximal power output. Before each time-to-exhaustion test, different dosages of LLLT (135, 270, and 405 J/thigh, respectively)
or placebo were applied at the quadriceps muscle bilaterally. Power output and muscle activation from both lower limbs were
recorded throughout the tests. Increased performance in time-to-exhaustion tests was observed with the LLLT-135 J (∼22 s;
P < .01), LLLT-270 J (∼13 s; P = .03), and LLLT-405 J (∼13 s; P = .02) compared to placebo (149 ± 23 s). Although LLLT-270 J
and LLLT-405 J did not show significant differences in muscle activation compared with placebo, LLLT-135 J led to an
increased high-frequency content compared with placebo in both limbs at the end of the exhaustion test (P ≤ .03). In conclusion,
LLLT increased time to exhaustion in competitive cyclists, suggesting this intervention as a possible nonpharmacological
ergogenic agent in cycling. Among the different dosages, LLLT-135 J seems to promote the best effects.
... It is reported that LLLT can prevent cell apoptosis, enhance cell adhesion, migration, and proliferation at low optical power levels which do not generate heat, sound, or vibarations [34]. One classic mechanism associated with LLLT effects on cell proliferation involves cell mitochondria absorbing laser energy [35]. Mitochondria as principle photoreceptors initiate a series of events, such as increased ATP, ROS, introcellular calcium, resulting in expression of many pro-proliferation gene, anti-apoptotic, and anti-oxidant products [17]. ...
3D printing has shown promise for neural regeneration by providing customized nerve scaffolds to structurally support and bridge the defect gap as well as deliver cells or various bioactive substances. Low-level light therapy (LLLT) exhibits positive effects on rehabiliation of degenerative nerves and neural disorders. With this in mind, we postulate that 3D printed neural scaffold coupling with LLLT will generate a new strategy to repair neural degeneration. To achieve this goal, we applied red laser light to stimualte neural stem cells on 3D printed scaffolds and investigated the subsequent cell response with respect to cell proliferation and differentiation. Here we show that cell prolifeartion rate and intracellular reactive oxgen species synthesis were significantly increased after 15 s laser stimulation follwed by 1 day culture. Over culturing time of 14 day in vitro, the laser stimulation promoted neuronal differentiation of neural stem cells, while the glial differentiation was suppressed based on results of both immunocytochemistry studies and real-time quantitative reverse transcription polymerase chain reaction testing. These findings suggest that integration of 3D printing and LLLT might provide a powerful methodology for neural tissue engineering.
... Furthermore, excessive production of ROS can result in oxidation of proteins, peroxidation of lipids and eventually cell death. LLLT can improve the activity of anti-oxidant enzymes through a photochemical process that accelerates the elimination of ROS [21]. This can be achieved at a molecular level by altering the conformation of anti-oxidant enzymes [22]. ...
Human immunodeficiency virus (HIV-1) infection remains a major health problem despite the use of highly active antiretroviral therapy (HAART), which has greatly reduced mortality rates. Due to the unavailability of an effective vaccine and treatment that would completely eradicate the virus in infected individuals, the quest for new therapies continues. Low level laser therapy (LLLT) involves the exposure of cells to low levels of red or infrared light. LLLT has been widely used in different medical conditions, but not in HIV-1 infection. This study aimed to determine the effects of LLLT on HIV-1 infected and uninfected TZM-bl cells. Both infected and uninfected cells were irradiated at a wavelength of 660 nm with different fluences from 2 J/cm(2) to 10 J/cm(2) . Changes in cellular responses were assessed using cell morphology, viability, proliferation, cytotoxicity and luciferase activity assays. Upon data analysis, uninfected irradiated cells showed no changes in cell morphology, viability, proliferation and cytotoxicity, while the infected irradiated cells did. In addition, laser irradiation reduced luciferase activity in infected cells. Finally, laser irradiation had no inhibitory effect in uninfected cells, whereas it induced cell damage in a dose dependent manner in infected cells.
... ROS has been reported to play a role in many aspects of HIV-1 pathogenesis such as increase in viral replication, reduced immune cell proliferation, loss of immune function, sensitivity to drug toxicity and chronic weight loss [6]. LLLT can improve the activity of anti- oxidant enzymes through a photochemical process that accelerates the elimination of ROS [7]. ...
HIV-1 epidemic remains a major health challenge. This study explores the effects of low level laser therapy on HIV-1 infected cells. Infection is reduced by irradiation and the mechanism needs to be investigated further.
... The decline in muscle strength and endurance that occurs with fatiguing exercise is thought to occur due to deficiencies in substrate bioavailability, blood flow, and tissue oxygenation, as well as the accumulation of metabolites and neuromuscular alterations [11,12]. There is evidence from both basic science and applied studies that PBM therapy may ameliorate disease processes by enhancing blood flow [6][7][8][13][14][15][16] and mitochondrial respiratory chain activity [9,17,18] to and within pathologic tissues. ...
Photobiomodulation (PBM) therapy has been implicated as an effective ergogenic aid to delay the onset of muscle fatigue. The purpose of this study was to examine the dose–response ergogenic properties of PBM therapy and its ability to prolong time to task failure by enhancing muscle activity and delaying the onset of muscle fatigue using a static positioning task. Nine participants (24.3 ± 4.9 years) received three doses of near-infrared (NIR) light therapy randomly on three separate sessions (sham, 240, and 480 J). For the positioning task, participants held a 30 % one-repetition maximum (1-RM) load using the index finger until volitional fatigue. Surface electromyography (sEMG) of the first dorsal interosseous muscle was recorded for the length of the positioning task. Outcomes included time to task failure (TTF), muscle fatigue, movement accuracy, motor output variability, and muscle activity (sEMG). The 240-J dose significantly extended TTF by 26 % (p = 0.032) compared with the sham dose. TTF for the 240-J dose was strongly associated with a decrease in muscle fatigue (R
2 = 0.54, p = 0.024). Our findings show that a 240-J dose of NIR light therapy is efficacious in delaying the onset and extent of muscle fatigue during submaximal isometric positioning tasks. Our findings suggest that NIR light therapy may be used as an ergogenic aid during functional tasks or post-injury rehabilitation.
... Laser phototherapy tested on fatigue in animal's lowered ROS production, decreased the influence of fatigue on muscle strength, and restored mitochondrial function[31]. In humans, Ferraresi et al.[10]and Toma et al.[13]explained that laser (808 nm) increases muscle performance through mitochondrial fusion or the formation of enlarged organelles, thus increasing adenosine triphosphate (ATP) synthesis and energy for the cell. ...
BACKGROUND: LED phototherapy can attenuate muscle fatigue and accelerate muscle recovery in young persons, but little is known about photobiomodulation effects on muscle strength in the elderly. OBJECTIVE: To assess the effects of LED phototherapy on the grip strength and muscle fatigue of wrist flexors in elderly women. METHODS: Twenty-nine women were recruited and allocated to Placebo Group (PG) (n = 14) and LED Group (LG) (n = 15). Grip strength, number of resisted wrist flexion repetitions, and serum creatine kinase (CK) were measured. The subjects were irradiated with one diode (638 nm, 150 mW, 11.7 J/cm2, 4.5 J/point) at four points on the wrist flexor muscles, and fatigue was induced by exercise using 75% of one maximum repetition (1MR). When muscle fatigue was reached, grip strength and CK were reassessed. RESULTS: In the LG, there was no intra-group difference for grip strength (N), 217.7 ± 34.3 to 209.9 ± 35.3 (p = 0.063) whereas in the PG, there was decrease in strength from 203.0 ± 22.5 to 181.4 ± 21.6 (p <0.001). LED increased the number of repetitions by 22.0%. An increase in CK (U/L) was observed in PG in all post-fatigue periods (p = 0.003) but no difference was found in the LG (p = 0.972). CONCLUSIONS: A single application of LED before muscle fatigue induction may effectively maintain grip strength and reduce muscle fatigue and damage.
... Fatigued muscles in the lower extremity require less force to reach muscle failure under high-intensity eccentricloading conditions 29,30 and to display negative effects on lower extremity biomechanics and neuromuscular fatigue. 31,32 Phototherapeutic effects linked to reinforcement of microcirculation, 33 enhanced adenosine triphosphate synthesis, 34 and mitochondrial function 35 have been observed after exposure to light. Reduced reactive oxygen species release and creatine phosphokinase activity and increased production of antioxidants and heat shock proteins have also been reported after PBM. ...
Context:
Recent studies suggest the prophylactic use of low-powered laser/light has ergogenic effects on athletic performance and postactivity recovery. Manufacturers of high-powered lasers/light devices claim that these can produce the same clinical benefits with increased power and decreased irradiation time; however, research with high-powered lasers is lacking.
Objective:
To evaluate the magnitude of observed phototherapeutic effects with 3 commercially available devices.
Design:
Randomized double-blind placebo-controlled study.
Setting:
Laboratory.
Patients or other participants:
Forty healthy untrained male participants.
Intervention(s):
Participants were randomized into 4 groups: placebo, high-powered continuous laser/light, low-powered continuous laser/light, or low-powered pulsed laser/light (comprising both lasers and light-emitting diodes). A single dose of 180 J or placebo was applied to the quadriceps.
Main outcome measure(s):
Maximum voluntary contraction, delayed-onset muscle soreness (DOMS), and creatine kinase (CK) activity from baseline to 96 hours after the eccentric exercise protocol.
Results:
Maximum voluntary contraction was maintained in the low-powered pulsed laser/light group compared with placebo and high-powered continuous laser/light groups in all time points (P < .05). Low-powered pulsed laser/light demonstrated less DOMS than all groups at all time points (P < .05). High-powered continuous laser/light did not demonstrate any positive effects on maximum voluntary contraction, CK activity, or DOMS compared with any group at any time point. Creatine kinase activity was decreased in low-powered pulsed laser/light compared with placebo (P < .05) and high-powered continuous laser/light (P < .05) at all time points. High-powered continuous laser/light resulted in increased CK activity compared with placebo from 1 to 24 hours (P < .05).
Conclusions:
Low-powered pulsed laser/light demonstrated better results than either low-powered continuous laser/light or high-powered continuous laser/light in all outcome measures when compared with placebo. The increase in CK activity using the high-powered continuous laser/light compared with placebo warrants further research to investigate its effect on other factors related to muscle damage.
... In addition, Patrocinio et al. 28 demonstrated that laser irradiation applied after a resistance training exercise program reduced lactate levels at rest and improved muscle fiber morphology, increasing muscle performance during a resistance exercise protocol. The beneficial effects of laser therapy on lactate removal may be related to the increase in microcirculation, the stimulation of mitochondrial activity, and the enhancement of ATP synthesis produced by LLLT 29 . ...
Background:
Low-level laser therapy (LLLT) has been demonstrated to be effective in optimizing skeletal muscle performance in animal experiments and in clinical trials. However, little is known about the effects of LLLT on muscle recovery after endurance training.
Objective:
This study evaluates the effects of low-level laser therapy (LLLT) applied after an endurance training protocol on biochemical markers and morphology of skeletal muscle in rats.
Method:
Wistar rats were divided into control group (CG), trained group (TG), and trained and laser irradiated group (TLG). The endurance training was performed on a treadmill, 1 h/day, 5 days/wk, for 8 wk at 60% of the maximal speed reached during the maximal effort test (Tmax) and laser irradiation was applied after training.
Results:
Both trained groups showed significant increase in speed compared to the CG. The TLG demonstrated a significantly reduced lactate level, increased tibialis anterior (TA) fiber cross-section area, and decreased TA fiber density. Myogenin expression was higher in soleus and TA muscles in both trained groups. In addition, LLLT produced myogenin downregulation in the TA muscle of trained animals.
Conclusion:
These results suggest that LLLT could be an effective therapeutic approach for stimulating recovery during an endurance exercise protocol.
... El uso de las emisiones infrarrojas generadas por el diodo láser Arsenurio de Galio (modelo CEC IR 10, Argentina) induce un sostenido alivio en una amplia gama de lesiones y afecciones articulares basado en su eficaz acción analgésica (Novoselova et al., 2006;Castano et al., 2007), antiinflamatoria (Fikácková et al., 2006) y cicatrizante (Kreisler et al., 2003;Reddy et al., 2004) como a nivel celular una acentuada síntesis proteica (Shefer et al., 2003;Simões et al., 2009), de DNA (Rizzi et al., 2006;Karu, 2008), de ATP mitocondrial (Hu et al., 2007;Xu et al., 2008) y de colágeno (Pereira et al., 2002;Cornejo et al., 2013) como así mismo modulando la proliferación celular (Vinck et al., 2003) las concentraciones de calcio citosólico (Lavi et al., 2003) y la actividad de variadas enzimas (Pastore et al., 2000;Kao & Sheen, 2003). ...
A total of 24 female Sprague-Dawley rats aged 4 months and weighing approximately 250 g, were divided into four groups labeled A, B, C and D. Group A received no infrared stimulation and served as control. Group B was radiated with a dose of 4 J/cm² of infrared laser, Group C with doses of 8 J/cm² and Group D with 16 J/cm². This infrared stimulation was carried out daily for 15 days uninterrupted. The rats were then sacrificed and samples of both normal-control liver and liver stimulated with the different infrared doses were extracted for immediate processing via transmission electron microscopy. Transmission electron microphotographs were obtained at magnifications of 21300X from both normal and stimulated hepatocytes; these were subjected to morphometric studies to determine volumetric fractions with special emphasis on the smooth endoplasmic reticulum (SER) and the following cell components: rough endoplasmic reticulum (RER), mitochondria, glycogen, eu and heterochromatin. Likewise, cell and nuclear areas were quantified. Analysis of the results of normal and stimulated hepatocytes with different infrared doses showed considerable differences in all the quantified cell components and particularly from the SER it is concluded that the effects of these stimulations bring about a drastic transformation in the ultrastructure and morphology of the hepatocytes, which may ultimately translate into a functional variation, thus representing the effect that these stimulations cause in this cell type.
... Lately, LLLT is used in cultured experiment,which has the effects on the survival of plasmids in Escherichia coli cells and the DNA repair with pulsed emission modes by low-level infrared laser action [16]. Furthermore, Khalid et al. illustrated LLLT is helpful in enhancing the proliferation rate of cell line [17].There are two alterations after receiving the low-intensity laser irradiation,which is modified in photoreceptor function and subsequent alterations in cellular signaling and cellular functions [18].The primary reactions have five hypotheses after light absorption,which are singlet-oxygen hypothesis, redox properties alteration hypothesis, nitric oxide hypothesis, transient local heating hypothesis, and superoxide anion hypothesis [19].The secondary reactions are a cellular signaling pathway which is the cell between photoacceptor and the nucleus inside [19] [20]. The chemical energy within the cell can be converted in the form of ATP, which leads to relief of pain and cell proliferation rates after the absorption of photonic energy [17]. ...
Low level laser therapy (LLLT) is effective in a lot of clinical treatments, but the photobiological basis of this therapy is not well understood. From our previous study, the effectiveness of laser acupuncture (LA) and cupping applied on low back pain (LBP) has been proved. However, the variation of the plasma cortisol level is unknown. Thus, this study aims to evaluate the effectiveness of LA and cupping on LBP by checking the plasma cortisol level. Fifty patients of either sex over 60 years old with LBP were recruited into a single blinded trial. Active group (LA plus soft cupping) and placebo group (sham LA plus soft cupping) were treated for five days. Laser, 40mW, wavelength 808nm, pulse rate 20Hz, was used to irradiate Weizhong (BL40) and Ashi acupoints for 10 minutes. The variation of VAS was recorded and blood samples were taken for the measurement of plasma cortisol levels. There was a significant fall in plasma cortisol in active group (p = 0.013) and placebo group (p = 0.039) after five days' treatment. This result showed that for the people with chronic LBP there is a beneficial effect if they continuously receive the treatment for five days. However, the combination of LA and cupping seems to quickly reduce the inflammation situation than placebo group did.
... LLLT promotes proliferation of multiple cells, which (especially red and near-infrared light) is mainly through the activation of mitochondrial respiratory chain and the initiation of cellular signaling. The alterations in photoacceptor function are the primary reactions, and the subsequent alterations in cellular signaling and cellular functions are secondary reactions [55]. The primary reactions after light absorption are singlet-oxygen hypothesis, redox properties alteration hypothesis, nitric oxide hypothesis, transient local heating hypothesis, and superoxide anion hypothesis [56]. ...
... Animal studies have demonstrated the positive effects of low-level laser therapy (LLLT) on reducing inflammation and improving muscle repair when used under optimal irradiation parameters [9][10][11]. LLLT is believed to improve mitochondrial function [12] and microcirculation and stimulate the respiratory chain, thereby increasing ATP synthesis [13,14]. Studies from our group showed that LLLT reduces local and systemic inflammation in HF rats [15]. ...
In heart failure (HF), there is an imbalance between the production of reactive oxygen species and the synthesis of antioxidant enzymes, causing damage to the cardiovascular function and increased susceptibility to DNA damage. The aim of this study was to evaluate the influence of low-level laser therapy (LLLT) on parameters of oxidative stress and DNA damage in skeletal muscle and plasma of rats with HF. Wistar rats were allocated into six groups: "placebo" HF rats (P-HF, n = 9), "placebo" Sham rats (P-sham, n = 8), HF rats at a dose 3 J/cm(2) of LLLT (3 J/cm(2)-HF, n = 8), sham rats at a dose 3 J/cm(2) of LLLT (3 J/cm(2)-sham, n = 8), HF rats at a dose 21 J/cm(2) of LLLT (21 J/cm(2)-HF, n = 8) and sham rats at a dose 21 J/cm(2) of LLLT (21 J/cm(2)-sham, n = 8). Animals were submitted to a LLLT protocol for 10 days at the right gastrocnemius muscle. Comparison between groups showed a significant reduction in superoxide dismutase (SOD) activity in the 3 J/cm(2)-HF group (p = 0.03) and the 21 J/cm(2)-HF group (p = 0.01) compared to the P-HF group. 2',7'-Dihydrodichlorofluorescein (DCFH) oxidation levels showed a decrease when comparing 3 J/cm(2)-sham to P-sham (p = 0.02). The DNA damage index had a significant increase either in 21 J/cm(2)-HF or 21 J/cm(2)-sham in comparison to P-HF (p = 0.004) and P-sham (p = 0.001) and to 3 J/cm(2)-HF (p = 0.007) and 3 J/cm(2)-sham (p = 0.037), respectively. Based on this, laser therapy appears to reduce SOD activity and DCFH oxidation levels, changing the oxidative balance in the skeletal muscle of HF rats. Otherwise, high doses of LLLT seem to increase DNA damage.
... Some physiological effects attributed to LLLT are related to soft tissue metabolism and can explain our findings. Across different disorders, increased microcirculation [29], enhanced ATP synthesis [30], and stimulation of mitochondrial respiratory chain [30] and mitochondrial function [31] have been observed after LLLT. Reduction of ROS release and creatine phosphokinase activity, and increased production of antioxidants and heat shock proteins, has also been reported after LLLT [32,33]. ...
Recent studies with phototherapy have shown positive results in enhancement of performance and improvement of recovery when applied before exercise. However, several factors still remain unknown such as therapeutic windows, optimal treatment parameters, and effects of combination of different light sources (laser and LEDs). The aim of this study was to evaluate the effects of phototherapy with the combination of different light sources on skeletal muscle performance and post-exercise recovery, and to establish the optimal energy dose. A randomized, double-blinded, placebo-controlled trial with participation of 40 male healthy untrained volunteers was performed. A single phototherapy intervention was performed immediately after pre-exercise (baseline) maximum voluntary contraction (MVC) with a cluster of 12 diodes (4 of 905 nm lasers-0.3125 mW each, 4 of 875 nm LEDs-17.5 mW each, and 4 of 670 nm LEDs-15 mW each- manufactured by Multi Radiance Medical™) and dose of 10, 30, and 50 J or placebo in six sites of quadriceps. MVC, delayed onset muscle soreness (DOMS), and creatine kinase (CK) activity were analyzed. Assessments were performed before, 1 min, 1, 24, 48, 72, and 96 h after eccentric exercise protocol employed to induce fatigue. Phototherapy increased (p < 0.05) MVC was compared to placebo from immediately after to 96 h after exercise with 10 or 30 J doses (better results with 30 J dose). DOMS was significantly decreased compared to placebo (p < 0.05) with 30 J dose from 24 to 96 h after exercise, and with 50 J dose from immediately after to 96 h after exercise. CK activity was significantly decreased (p < 0.05) compared to placebo with all phototherapy doses from 1 to 96 h after exercise (except for 50 J dose at 96 h). Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage.
... Dessa forma, a LBP pode ser útil para aumentar o desempenho muscular. Em um estudo recente, de Xu et al. 17 , a LBP aumentou a função mitocondrial em células musculares sob doses de 0,33-8,22 J/cm 2 ; e doses de LBP de 0,33 e 1,338 J/cm 2 reverteram o estado de disfunção mitocondrial induzida pela estimulação elétrica. ...
Skeletal muscle fatigue is a novel research area in laser therapy, there being few studies carried out. Though low-level laser therapy (LLLT) applied prior to exercise has showed positive results in delaying skeletal muscle fatigue, no studies could be found that measured muscle performance and fatigue by means of isokinetic dynamometry. This clinical trial aims at assessing the effects of LLLT (655 nm, 50 mW and 12 J total energy delivered) on anterior tibialis muscle performance and fatigue by means of isokinetic dynamometry (30 concentric-mode repetitions at 240º.sec-1 angular speed) in 14 healthy male subjects. Results show that, when volunteers had been treated with LLLT prior to exercise, torque peak values (30.91±5.86 N.m) were significantly higher than those of three previous measurements with no LLLT (24.92±7.45 N.m, p<0.001; 26.83±7.74 N.m, p<0.01; and 26.00±7.88 N.m, p<0.001). However, no decrease in fatigue indexes could be found. It may thus be said that LLLT increased skeletal muscle torque in irradiated muscles, but had no effect on muscle fatigue.
... LLLT also improves levels of biological markers directly related to the recovery of the musculoskeletal system when applied before [19], during [20] or after [21] the execution of physical exercise. This therapeutic modality seems to improve muscle performance via the energy metabolism in cells by stimulating photochemical events and enhancing mitochondrial function in muscle cells [22]. The structural changes in the mitochondria (size) promoted by LLLT lead to an improvement in cell respiration and the formation of adenosine triphosphate, which provides energy to the cells [23]. ...
Background:
Type 2 diabetes, also known non-insulin-dependent diabetes, is the most prevalent type of the disease and involves defects in the secretion and action of insulin. The aim of the proposed study is to evaluate the efficacy of pre-exercise low-level laser therapy (LLLT) on muscle performance of the quadriceps femoris in individuals with type 2 diabetes.
Methods/design:
A double-blind, randomized, controlled clinical trial will be carried out in two treatment phases. In the first phase, quadriceps muscle performance will be evaluated using an isokinetic dynamometer and the levels of creatine kinase and lactate dehydrogenase (biochemical markers of muscle damage) will be determined. The participants will then be allocated to four LLLT groups through a randomization process using opaque envelopes: Group A (4 Joules), Group B (6 Joules), Group C (8 Joules) and Group D (0 Joules; placebo). Following the administration of LLLT, the participants will be submitted to an isokinetic eccentric muscle fatigue protocol involving the quadriceps muscle bilaterally. Muscle performance and biochemical markers of muscle damage will be evaluated again immediately after as well as 24 and 48 hours after the experimental protocol. One week after the last evaluation the second phase will begin, during which Groups A, B and C will receive the LLLT protocol that achieved the best muscle performance in phase 1 for a period of 4 weeks. At the end of this period, muscle performance will be evaluated again. The protocol for this study is registered with the World Health Organization under Universal Trial Number U1111-1146-7109.
Discussion:
The purpose of this randomized clinical trial is to evaluate the efficacy of pre-exercise LLLT on the performance of the quadriceps muscle (peak torque, total muscle work, maximum power and fatigue index - normalized by body mass) in individuals with DM-2. The study will support the practice of evidence-based to the use of LLLT in improving muscle performance in Individuals with DM-2. Data will be published after the study is completed.
... Antimycin is a mitochondrial inhibitor that binds in the energy-coupling site and inhibits the flow of electrons from cytochrome b to cytochrome c 1 . Low-intensity laser irradiation has been reported to improve mitochondrial dysfunction and leads to mitochondrial alterations [24,25]. The inhibition of LLLT-induced CCL2 mRNA expression by oligomycin and antimycin suggested mitochondrial involvement ( Figure 4). ...
Low-level laser therapy (LLLT) has been used in the treatment of radiotherapy-induced oral mucositis and allergic rhinitis. However, the effects of LLLT on human monocyte polarization into M1 macrophages are unknown. To evaluate the effects of LLLT on M1-related cytokine and chemokine production and elucidate the mechanism, the human monocyte cell line THP-1 was treated with different doses of LLLT. The expression of M1-related cytokines and chemokines (CCL2, CXCL10, and TNF- α ) was determined by ELISA and real-time PCR. LLLT-associated histone modifications were examined by chromatin immunoprecipitation (ChIP) assays. Mitochondrial involvement in the LLLT-induced M1-related cytokine expression was evaluated by quantitative real-time PCR. Flow cytometry was used to detect the cell surface markers for monocyte polarization. The results showed that LLLT (660 nm) significantly enhanced M1-related cytokine and chemokine expression in mRNA and protein levels. Mitochondrial copy number and mRNA levels of complex I-V protein were increased by LLLT (1 J/cm(2)). Activation of M1 polarization was concomitant with histone modification at TNF- α gene locus and IP-10 gene promoter area. This study indicates that LLLT (660 nm) enhanced M1-related cytokine and chemokine expression via mitochondrial biogenesis and histone modification, which may be a potent immune-enhancing agent for the treatment of allergic diseases.
Purpose
Despite its susceptibility to muscle fatigue, combined neuromuscular electrical stimulation (NMES) and blood flow restriction (BFR) is an effective regimen for managing muscle atrophy when traditional resistance exercises are not feasible. This study investigated the potential of low-level laser therapy (LLLT) in reducing muscle fatigue after the application of combined NMES and BFR.
Methods
Thirty-six healthy adults were divided into control and LLLT groups. The LLLT group received 60 J of 850 nm wavelength LLLT before a training program of combined NMES and BFR of the non-dominant extensor carpi radialis longus (ECRL). The control group followed the same protocol but received sham laser therapy. Assessments included maximal voluntary contraction (MVC), ECRL mechanical properties, and isometric force-tracking for wrist extension.
Results
The LLLT group exhibited a smaller normalized difference in MVC decrement (-4.01 ± 4.88%) than the control group (-23.85 ± 7.12%) ( P < .001). The LLLT group demonstrated a smaller decrease in muscle stiffness of the ECRL compared to the control group, characterized by the smaller normalized changes in frequency ( P = .002), stiffness ( P = .002), and relaxation measures ( P = .011) of mechanical oscillation waves. Unlike the control group, the LLLT group exhibited a smaller post-test increase in force fluctuations during force-tracking ( P = .014), linked to the predominant recruitment of low-threshold MUs ( P < .001) without fatigue-related increases in the discharge variability of high-threshold MUs ( P > .05).
Conclusions
LLLT pre-exposure reduces fatigue after combined NMES and BFR, preserving force generation, muscle stiffness, and force scaling. The functional benefits are achieved through fatigue-resistant activation strategies of motor unit recruitment and rate coding.
Amaç: Kemoterapi ile indüklenmiş periferik nöropati (KİPN), kemoterapötik ilaçların yan etkisiyle oluşmaktadır. Sisplatin sonucu oluşan nöron kayıplarını minimalize etmek için farmakolojik ajanlar ve fotobiyostimülatörler kemoterapi ile indüklenen periferik nöropati tedavisinde kullanılmaktadır. Ancak bu metotların etki mekanizması ve kullanım etkinlikleri net değildir, araştırılmaktadır. Bu tez çalışmasında, kuersetin ve düşük seviyeli lazer tedavisinin sisplatin ile indüklenmiş in vitro periferik nöropati modeli üzerindeki etkisinin incelenmesi amaçlanmıştır.
Gereç ve Yöntem: Çalışma için PC12 hücre hattı kullanılmıştır. Sisplatin ile periferik nöropai modeli oluşturulan hem farklılaştırılmış hem de farklılaştırılmamış PC12 hücrelerine, kuersetin ve düşük seviyeli lazer tedavi uygulanmıştır. Uygulama yapılan hücrelere hücre canlılığı, apoptoz, mitokondriyal membran potansiyeli, LDH, RT-PCR analizleri yapılmıştır.
Bulgular: Analiz sonuçlarına göre sisplatinin hem farklılaştırılmamış hem de farklılaştırılmış PC12 hücrelerinde apoptoz, mitokondriyal membran potansiyelinde, LDH oranlarında artışa, hücre canlılığında, GAP-43 ve Synapsin I gen ekspresyonlarında azalmaya sebep olduğu bulunmuştur. Sisplatin ile indüklenen periferik nöropati modeli oluşturulan hem farklılaştırılmış hem de farklılaştırılmamış PC12 hücrelerine ayrı ayrı uygulanan kuersetin ve DSLT gruplarda ise apoptoz, mitokondriyal membran potensiyelinde, LDH oranlarında azalma, hücre canlılığında, GAP-43 ve Synapsin I gen ekspresyonlarında artışa neden olduğu belirlenmiştir. Ancak kombine tedavi (kuersetin ve DSLT) uygulanan gruplarda ise sisplatin uygulanan gruplar arasında istatiksel olarak bir fark görülmemiştir.
Sonuç: Sisplatin ile indüklenen periferik nöropatide kuersetin ve düşük seviyeli lazer tedavisinin uygun dozları belirlenmiştir. Ancak kombine tedavinin etkinliği görülmemiştir. Gelecek çalışmalarda kombine tedavinin mekanizması araştırılacaktır.
Background
We examined the effect of low-level laser therapy (LLLT) and Bioptron light therapy on pain and function following primary total knee arthroplasty.
Methods
A single-center, single-surgeon, prospective randomized clinical trial was performed with 3 groups of 15 patients: LLLT (804 nm), light (Bioptron; Bioptron AG, Wollerau, Switzerland), and controls. Range of motion (ROM), visual analog scale pain, opiate consumption (oxycodone in milligrams), knee swelling, and the Knee Society Score (KSS) were assessed before the surgery and on postoperative day 2, postoperative day 3, month 3, and month 12 after the operation.
Results
The preoperative scores were similar between groups. A higher ROM was observed with the LLLT group at all follow-ups except at the 12-month follow-up (3-month ROM: 116.8° vs 104.0° vs 92.3°; P < .001). The knee swelling at 3 months was similar between the LLLT and light groups (2.1 cm), which was lower than that in controls (2.1 cm, P < .001). Furthermore, visual analog scale pain decreased more in the LLLT group than in other groups (8.5 vs 7.2 vs 6.0 points) at 3 months (P = .04) but was similar at 12 months (P > .05). Also, the LLLT group consumed fewer opiate painkillers during the first month (48.3 vs 60.3 mg of oxycodone, P = .02). In the LLLT group, the KSS at 3 and 12 months and the KSS function score at 3 months exceeded minimally clinically important differences (P < .05).
Conclusions
In the early stages of recovery after total knee arthroplasty, LLLT and Bioptron light therapy could be helpful to control immediate and acute knee pain and swelling, reduce the need for opioids, improve ROM and functional scores, and improve recovery.
Level of Evidence
Therapeutic level I.
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.
Recently, photobiomodulation therapy (PBMT) using laser or light emitting diode (LED) as a light source has been used as a treatment for sports-related disorders. Until now, lasers or LEDs have been mainly used, but a light source that combines laser and LED is also used. In this paper, we will introduce the effects of PBMT before and after exercise, and the effects of PBMT on muscle damage, focusing on recent research reports, and discuss the possibility of using PBMT in clinical settings in future.
Background:
Photobiomodulation (PBM) has been studied mainly for its effects on the repair, regeneration, and healing of tissue due to its direct and indirect actions on cell proliferation. However, it is necessary to consider the way in which laser acts, that is, whether it affects the rates of spontaneous mutation and mitotic recombination of cells.
Objective:
This study investigated the genotoxic potential of PBM (904 nm) based on an in vivo bioassay that concomitantly evaluates mitotic recombination and point and chromosomal mutations.
Methods:
Strains of Drosophila melanogaster that carry specific marker genes were used to detect the induction of mutation and somatic recombination when exposed to different fluences (3, 5, 10, and 20 J/cm2). DNA damage was measured using the somatic mutation and recombination test (SMART), which is based on the identification of wing hair with mutant phenotypes that express lesions at DNA level.
Results:
The doses 5, 10, and 20 J/cm2 induced significant increase in the total number of spots compared with the negative control. The highest frequency of spots was caused by the 10 J/cm2.
Conclusions:
Besides recombination events, the quantitative and qualitative analysis of mutant hairs revealed the occurrence of mutagenic events, both punctual and chromosomal. In addition, the results point to a dose-dependent response.
The vesicular monoamine transporter 2 (VMAT2) pumps dopamine from cytoplasm into synaptic vesicles for subsequent release, and the deficits of VMAT2 has been implicated in the dopaminergic neuronal cell loss which is considered as a typical pathological feature of Parkinson's disease (PD). Low-power laser irradiation (LPLI), a potent noninvasive physiotherapy approach, is capable of penetrating into nerve tissue to exert beneficial effects such as promoting nerve regeneration and ATP production. In the present study, we demonstrated that LPLI protects against MPP⁺-induced neurotoxicity via upregulation of VMAT2 in SH-SY5Y human dopaminergic neuroblastoma cells. The photoactivation of ERK phosphorylated cAMP-response element binding protein (CREB) at Ser133, and thus increased the ability of CREB binding to the promoter region of VMAT2, leading to elevated VMAT2 expression, which contributes to dopamine release and cell survival. Taken together, for the first time to our knowledge, the results showed that LPLI attenuates MPP⁺-induced neurotoxicity through activation of ERK/CREB/VMAT2 pathway, suggesting that the manipulation of VMAT2 by LPLI may provide a potential therapeutic strategy for PD.
Mitochondrial abnormality is a predominant pathological feature in aging and neurodegenerative diseases including Alzheimer's disease (AD). This chapter reviews AD-related pathological changes in mitochondrial structure and function and discusses the potential of targeting mitochondria as an effective treatment for the disease. Mitochondrial dysfunction has been implicated in various human pathological conditions such as neurodegenerative diseases. The chapter focuses on how mitochondrial-targeted therapeutic approaches may be beneficial specifically for AD. Currently, MitoQ and SS31 are the most studied mitochondria-targeted antioxidants in AD. MitoQ and SS31 have been shown to protect against Aβ toxicity in neurons from an AD mouse model. However, other mitochondrial functions such as Ca²⁺ signaling and mitochondrial respiration also serve as attractive drug targets.
The cerebrovascular accident (CVA), high-impact disease II, affects the basic functions of the limbs, leading to changes of sensory, language, and motor functions. The search for resources that minimize the damage caused by this disease grows every day. The clinical use of low-intensity laser therapy (LILT) has provided major breakthroughs in the treatment of muscular disorders and prevention of muscle fatigue. Thus, the objective of the present study is to analyze the answers and immediate adaptations of the rectus femoris and vastus medialis of spastic hemiparetic patients, facing the increase in peak torque and triggering muscle fatigue, after application of LILT. Double-blind clinical trials were conducted with 15 volunteers post-CVA with spasticity, of both genders, between 40 and 80 years old. To this end, the volunteers went through three consecutive stages of rating (control, placebo, and laser). All performed tests of isometric contraction on the patient's hemiparetic side. Significant differences were observed with regard to the increase in muscle performance (p = 0.0043) and the reduction in blood lactate concentration (p < 0.0001) of the post-LILT muscles. The LILT (diode laser, l100 mW 808 nm, 4.77 J/cm(2)/point, 40 s/AP) can be employed during and after spastic muscle-strengthening exercises, contributing to the improvement of motor function of the patient. After application of LILT, we found increased torque as well as decreased in lactate level in patients with spasticity.
We investigated the effects of low power 830 nm near-infrared and 680 nm far-red laser light on Jurkat cells mitochondrial reticulum size and shape. The 1.8 μJ/cell total dose near-infrared laser irradiation induced moderate mitochondrial volume and mass decrease, and substantial fragmentation of the network. Double total dose engendered parameter changes appeared massive or mild depending on the irradiation regime. Quadruple total dose produced changes were moderate as compared to those induced by double doses. Mild cyanide intoxication caused large mitochondrial mass decrease, while higher poisoning levels did not. The 1.3 μJ/cell total dose far-red laser irradiation induced mitochondrial mass changes were sensitively dependent on cells cyanide poisoning degree. Altogether our data demonstrate significant, cell state, laser wavelength, laser dose, and irradiation regime dependent, photobiomodulation of mitochondrial volume/mass and morphology in noninjured and metabolically stressed human T leukemia lymphoblasts.
Oxidative stress is the term generally used to describe the damage caused by imbalance between pro-oxidants and antioxidants in the organism. The increase in the O2 consumption induced by physical exercise is associated with the increase of reactive oxygen species (ROS) being these species inducers of oxidative stress. Although the evidence indicates a probable inhibitory effect of the light emitting diode therapy (LEDT) on the production of ROS, there are no studies observing this effect in humans. This preliminary study has the aim to verify the effects of LEDT applied before high-intensity exercise on lipid peroxidation, measured through blood levels of ThioBarbituric Acid Reactive Substances (TBARS). Six male volleyball athletes were submitted to two situations: active LEDT and placebo LEDT. Performance in the exercise protocol showed no difference (p> 0.05) between the two situations in peak power, average power and fatigue index. The results related to lipid peroxidation were: at active LEDT situation, it was not possible to observe statistically significant difference (p>0.05) between pre and post exercise levels (6.98 ± 0.81 and 7.02 ± 0.47 nmol/ mL); at placebo LEDT situation, statistically significant difference (p=0.05) was observed between pre and post exercise levels (7.09 ± 1.28 and 8.43 ± 0.71 nmol/mL). These results show that active LEDT seems to be effective in controlling lipid peroxidation in athletes submitted to intense exercise.
Photobiomodulation (PBM) is a nondamaged modulation of laser irradiation or monochromatic light (LI) on a biosystem function. It depends on whether the function is in its function-specific homeostasis (FSH). An FSH is a negative-feedback response of a biosystem to maintain the function-specific conditions inside the biosystem so that the function is perfectly performed. A function in its FSH is called a normal function. A function far from its FSH is called a dysfunctional function. The process of a function from dysfunctional to normal is called a functional normalization. For a normal function in its FSH, there are FSH-essential subfunctions (FESs), FSH-nonessential subfunctions (FNSs), and an FES/FNS-specific homeostasis (FESH/FNSH). A FSH can resist internal/external disturbances under the threshold, but can be disrupted by an FSH-specific stress (FSS). A normal/dysfunctional FSS is called a successful/chronic stress. An FESH/FNSH-specific stress was called an extraordinary/ordinary stress. A low level LI (LLL) cannot directly affect a normal function, but can modulate a chronic stress. A normal function may have a chronic ordinary stress, and an LLL may modulate the chronic ordinary stress so that it promotes the normalization of the dysfunctional FNS and then upgrades the normal function. A high level LI can modulate a normal function and may be a successful stress.
Photobiomodulation (PBM) is a modulation of laser irradiation or monochromatic light (LI) on biosystems. There is little research on PBM dynamics although its phenomena and mechanism have been widely studied. The PBM was discussed from dynamic viewpoint in this paper. It was found that the primary process of cellular PBM might be the key process of cellular PBM so that the transition rate of cellular molecules can be extended to discuss the dose relationship of PBM. There may be a dose zone in which low intensity LI (LIL at different doses) has biological effects similar to each other, so that biological information model of PBM might hold. LIL may self-adaptively modulate a chronic stress until it becomes successful.
Background and Objective
The effects of low-level laser light irradiation are still highly contested, and the mechanisms of its action still unclear. This study was conducted to test the effects of low-level laser irradiation at 660 nm on human lymphocytes and to investigate the possible mechanisms by which these effects are produced.Study Design/Materials and Methods
Whole blood obtained by phlebotomy was irradiated at 660 nm by using energy fluences between 0 and 5.0 J/cm2. The lymphocytes were isolated after irradiation of the whole blood. For the control experiment, the lymphocytes were first isolated and then irradiated at the same wavelength and energy fluence for comparison. The proliferation of lymphocytes and the formation of free radicals and lipid peroxides were monitored. Hemoglobin was also irradiated in a cell-free environment to test for the production of lipid peroxides.ResultsLymphocyte proliferation was significantly higher (P < 0.05) as expressed by a Stimulation Index in samples irradiated in the presence of whole blood compared with lymphocytes irradiated after isolation from whole blood. Free radical and lipid peroxide production also increased significantly when samples were irradiated in the presence of red blood cells.Conclusion
The present study supports the hypothesis that one mechanism for the photobiostimulation effect after irradiation at 660 nm is the reaction of light with hemoglobin, resulting in oxygen radical production. Lasers Surg. Med. 27:255–261, 2000 © 2000 Wiley-Liss, Inc.
Background
In medicine, lasers have been used predominantly for applications, which are broadly termed low level laser therapy (LLLT), phototherapy or photobiomodulation. This study aimed to establish cellular responses to Helium-Neon (632.8 nm) laser irradiation using different laser fluences (0.5, 2.5, 5, 10, and 16 J/cm2) with a single exposure on 2 consecutive days on normal and wounded human skin fibroblasts.Materials and Methods
Changes in normal and wounded fibroblast cell morphology were evaluated by light microscopy. Changes following laser irradiation were evaluated by assessing the mitochondrial activity using adenosine triphosphate (ATP) luminescence, cell proliferation using neutral red and an alkaline phosphatase (ALP) activity assay, membrane integrity using lactate dehydrogenase (LDH), and percentage cytotoxicity and DNA damage using the Comet assay.ResultsMorphologically, wounded cells exposed to 5 J/cm2 migrate rapidly across the wound margin indicating a stimulatory or positive influence of phototherapy. A dose of 5 J/cm2 has a stimulatory influence on wounded fibroblasts with an increase in cell proliferation and cell viability without adversely increasing the amount of cellular and molecular damage. Higher doses (10 and 16 J/cm2) were characterized by a decrease in cell viability and cell proliferation with a significant amount of damage to the cell membrane and DNA.Conclusions
Results show that 5 J/cm2 stimulates mitochondrial activity, which leads to normalization of cell function and ultimately stimulates cell proliferation and migration of wounded fibroblasts to accelerate wound closure. Laser irradiation can modify cellular processes in a dose or fluence (J/cm2) dependent manner. Lasers Surg. Med. 38:74–83, 2006. © 2006 Wiley-Liss, Inc.
In animal and clinical trials low-level laser therapy (LLLT) using red, infrared and mixed wavelengths has been shown to delay the development of skeletal muscle fatigue. However, the parameters employed in these studies do not allow a conclusion as to which wavelength range is better in delaying the development of skeletal muscle fatigue. With this perspective in mind, we compared the effects of red and infrared LLLT on skeletal muscle fatigue. A randomized double-blind placebo-controlled crossover trial was performed in ten healthy male volunteers. They were treated with active red LLLT, active infrared LLLT (660 or 830 nm, 50 mW, 17.85 W/cm(2), 100 s irradiation per point, 5 J, 1,785 J/cm(2) at each point irradiated, total 20 J irradiated per muscle) or an identical placebo LLLT at four points of the biceps brachii muscle for 3 min before exercise (voluntary isometric elbow flexion for 60 s). The mean peak force was significantly greater (p < 0.05) following red (12.14%) and infrared LLLT (14.49%) than following placebo LLLT, and the mean average force was also significantly greater (p < 0.05) following red (13.09%) and infrared LLLT (13.24%) than following placebo LLLT. There were no significant differences in mean average force or mean peak force between red and infrared LLLT. We conclude that both red than infrared LLLT are effective in delaying the development skeletal muscle fatigue and in enhancement of skeletal muscle performance. Further studies are needed to identify the specific mechanisms through which each wavelength acts.
This study aims to analyze the effects of low-level laser therapy (LLLT) on the oxidative activity and the expression/activity of metalloproteinases of the masseter muscle.
Currently in dentistry LLLT has been used on patients with muscular disorders, such as the temporomandibular disorders (TMDs) but its effect at the cellular level has not been fully elucidated.
Thirty male Wistar rats divided into 6 groups (n=5) received 10 laser irradiations (780 nm, 5 mmW, CW laser, illuminated area 0.04 cm(2), power density 125 mW/cm(2)), with different energy densities (group I-0; group II-0.5; group III-1.0; group IV-2.5; group V-5.0; and group VI-20 J/cm(2)). Muscles were processed for nicotinamide adenine dinucleotide diaphorase (NADH) and sucinate dehydrogenase (SDH) activities and zymography. The photomicrographs were evaluated by the point counting method using a test system and ImageJ software; and by the ANOVA statistical test. The proteinases' secretion/activity was qualitatively analyzed by zymography.
LLLT significantly increased (p<0.05) masseter muscle oxidative metabolism shown by the increased area of intermediary fibers in the NADH (groups IV, V, and VI) and SDH (group V) reactions. The same metabolic pattern was observed among the groups in both reactions. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) zymography detected only the MMP-2 expression/activity for the untreated-control group (group I). The exposure to LLLT increased the activity of MPP-2 in group VI and the activity of MMP-9 in all groups exposed to different energy densities of laser irradiation (groups II, III, IV, V, and VI).
Thus, LLLT stimulated the oxidative metabolism and the expression of matrix metalloproteinase (MMPs) of the masseter muscle, which may indicate a matrix remodeling process. However, group VI did not show the best results for oxidative metabolism, probably indicating that the dosage they were given was high for this protocol.
The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots - 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p = 0.01; time to exhaustion, p = 0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p = 0.0001) and protein (p = 0.0230) damages, as well as the activities of SOD (p = 0.0034), CK (p = 0.0001) and LDH (p = 0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.
In the last years, phototherapy has becoming a promising tool to improve skeletal muscle recovery after exercise, however, it was not compared with other modalities commonly used with this aim. In the present study we compared the short-term effects of cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) with placebo LEDT on biochemical markers related to skeletal muscle recovery after high-intensity exercise. A randomized double-blind placebo-controlled crossover trial was performed with six male young futsal athletes. They were treated with CWIT (5°C of temperature [SD ±1°]), active LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW of output power, 30 s of irradiation time per point, and 41.7 J of total energy irradiated per point, total of ten points irradiated) or an identical placebo LEDT 5 min after each of three Wingate cycle tests. Pre-exercise, post-exercise, and post-treatment measurements were taken of blood lactate levels, creatine kinase (CK) activity, and C-reactive protein (CRP) levels. There were no significant differences in the work performed during the three Wingate tests (p > 0.05). All biochemical parameters increased from baseline values (p < 0.05) after the three exercise tests, but only active LEDT decreased blood lactate levels (p = 0.0065) and CK activity (p = 0.0044) significantly after treatment. There were no significant differences in CRP values after treatments. We concluded that treating the leg muscles with LEDT 5 min after the Wingate cycle test seemed to inhibit the expected post-exercise increase in blood lactate levels and CK activity. This suggests that LEDT has better potential than 5 min of CWIT for improving short-term post-exercise recovery.
There are some indications that low-level laser therapy (LLLT) may delay the development of skeletal muscle fatigue during high-intensity exercise. There have also been claims that LED cluster probes may be effective for this application however there are differences between LED and laser sources like spot size, spectral width, power output, etc. In this study we wanted to test if light emitting diode therapy (LEDT) can alter muscle performance, fatigue development and biochemical markers for skeletal muscle recovery in an experimental model of biceps humeri muscle contractions.
Ten male professional volleyball players (23.6 [SD +/-5.6] years old) entered a randomized double-blinded placebo-controlled crossover trial. Active cluster LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW, 30 seconds total irradiation time, 41.7 J of total energy irradiated) or an identical placebo LEDT was delivered under double-blinded conditions to the middle of biceps humeri muscle immediately before exercise. All subjects performed voluntary biceps humeri contractions with a workload of 75% of their maximal voluntary contraction force (MVC) until exhaustion.
Active LEDT increased the number of biceps humeri contractions by 12.9% (38.60 [SD +/-9.03] vs. 34.20 [SD +/-8.68], P = 0.021) and extended the elapsed time to perform contractions by 11.6% (P = 0.036) versus placebo. In addition, post-exercise levels of biochemical markers decreased significantly with active LEDT: Blood Lactate (P = 0.042), Creatine Kinase (P = 0.035), and C-Reative Protein levels (P = 0.030), when compared to placebo LEDT.
We conclude that this particular procedure and dose of LEDT immediately before exhaustive biceps humeri contractions, causes a slight delay in the development of skeletal muscle fatigue, decreases post-exercise blood lactate levels and inhibits the release of Creatine Kinase and C-Reative Protein. Lasers Surg. Med. 41:572-577, 2009. (c) 2009 Wiley-Liss, Inc.
The effect of photobiomodulation on delayed onset muscle soreness remains unknown. This study represents the first investigation of this treatment using an animal model.
Seventy-two Sprague-Dawley rats were randomly divided into five groups: sedentary control group, exercise control group and three exercise-plus-laser groups. Downhill running was used to induce muscle injury in the gastrocnemius muscle. He-Ne laser irradiations were administered to the injured muscles immediately and at 18 and 42 h after exercise in the three exercise-plus-laser groups at 12, 28, and 43 J/cm2, respectively. Histological examination and serum creatine kinase (CK), muscle superoxide dismutase (SOD) and malondialdehyde (MDA) analyses were done at 24 and 48 h after exercise.
The exercise control group exhibited a marked inflammation in the gastrocnemius muscle and significant elevations in serum CK activity and muscle MDA level after downhill running. He-Ne laser irradiation at 43 J/cm2 inhibited muscle inflammation, significantly enhanced muscle SOD activity and significantly reduced serum CK activity and muscle MDA level at both 24 and 48 h after exercise, whereas the irradiation at 12 or 28 J/cm2 slightly inhibited muscle inflammation and significantly reduced serum CK activity at 48 h after exercise only (P<0.05).
Low-level He-Ne laser therapy could exert therapeutic effects on eccentric exercise-induced rat muscle injury through enhancing muscle anti-oxidative capacity and reducing the inflammatory reaction. The photobiomodulation was dose-dependent, and the 43 J/cm2 dose was the most efficient among the doses used.
BACKGROUND DATA AND OBJECTIVE: There is anecdotal evidence that low-level laser therapy (LLLT) may affect the development of muscular fatigue, minor muscle damage, and recovery after heavy exercises. Although manufacturers claim that cluster probes (LEDT) maybe more effective than single-diode lasers in clinical settings, there is a lack of head-to-head comparisons in controlled trials. This study was designed to compare the effect of single-diode LLLT and cluster LEDT before heavy exercise.
This was a randomized, placebo-controlled, double-blind cross-over study. Young male volleyball players (n = 8) were enrolled and asked to perform three Wingate cycle tests after 4 x 30 sec LLLT or LEDT pretreatment of the rectus femoris muscle with either (1) an active LEDT cluster-probe (660/850 nm, 10/30 mW), (2) a placebo cluster-probe with no output, and (3) a single-diode 810-nm 200-mW laser.
The active LEDT group had significantly decreased post-exercise creatine kinase (CK) levels (-18.88 +/- 41.48 U/L), compared to the placebo cluster group (26.88 +/- 15.18 U/L) (p < 0.05) and the active single-diode laser group (43.38 +/- 32.90 U/L) (p < 0.01). None of the pre-exercise LLLT or LEDT protocols enhanced performance on the Wingate tests or reduced post-exercise blood lactate levels. However, a non-significant tendency toward lower post-exercise blood lactate levels in the treated groups should be explored further.
In this experimental set-up, only the active LEDT probe decreased post-exercise CK levels after the Wingate cycle test. Neither performance nor blood lactate levels were significantly affected by this protocol of pre-exercise LEDT or LLLT.
Contractile activity induces adaptations in the expression of genes encoding skeletal muscle mitochondrial proteins; however, the putative signals responsible for these adaptations remain unknown. We used electrical stimulation (5 Hz, 65 V) of C2C12 muscle cells in culture to define some of the mechanisms involved in contractile activity-induced changes in cytochrome c gene expression. Chronic contractile activity (4 days, 3 h/day) augmented cytochrome c mRNA by 1.6-fold above control cells. This was likely mediated by increases in transcriptional activation, because cells transfected with full-length (-726 base pairs) or minimal (-66 base pairs) cytochrome c promoter/chloramphenicol acetyltransferase reporter constructs demonstrated contractile activity-induced 1.5-1.7-fold increases in the absence of contractile activity-induced increases in mRNA stability. Transcriptional activation of the -726 promoter was abolished when muscle contraction was inhibited at various subcellular locations by pretreatment with either the Na(+) channel blocker tetrodotoxin, the intracellular Ca(2+) chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester, or the myosin ATPase inhibitor 2,3-butanedione monoxime. It was further reduced in unstimulated cells when mitochondrial ATP synthesis was impaired using the uncoupler 2,4-dinitrophenol. Because the contractile activity-induced response was evident within the minimal promoter, electromobility shift assays performed within the first intron (+75 to +104 base pairs) containing Sp1 sites revealed an elevated DNA binding in response to contractile activity. This was paralleled by increases in Sp1 protein levels. Sp1 overexpression studies also led to increases in cytochrome c transactivation and mRNA levels. These data suggest that variations in the rate of mitochondrial ATP synthesis are important in determining cytochrome c gene expression in muscle cells and that this is mediated, in part, by Sp1-induced increases in cytochrome c transcription.
To examine changes in contractile properties and mechanisms of fatigue during submaximal nontetanic skeletal muscle activity, in situ perfused soleus (60-min protocol) and extensor digitorum longus (EDL; 10-min protocol) muscles of the rat were electrically stimulated intermittently at low frequency. The partly fused trains of contractions showed a two-phase change in appearance. During the first phase, relaxation slowed, one-half relaxation time increased, and maximal relaxation first derivative of force (dF/dt) decreased. Developed force during the trains was reduced and was closely related to the rate of relaxation in this first phase. During the second phase, relaxation became faster again, one-half relaxation time decreased, and force returned to resting levels between contractions in a train. In contrast, developed force remained reduced, so that peak force of the contractions was 51% (soleus) and 30% (EDL) of control. In the soleus muscle, the changes in contractile properties were not related to ATP, creatine phosphate, or lactate content. The changes in contractile properties fit best with a mechanism of fatigue involving changes in Ca(2+) handling by the sarcoplasmic reticulum.
Excitability in muscle cells manifests itself as contractility and may be evoked by electrical stimulation. Here we describe an electrical stimulator device applicable to cells seeded on standard multiwell plates and demonstrate how it effectively stimulates synchronous contraction of skeletal muscle C2C12 cells without damaging them. The electrical stimulator of cultured cells (ESCC) consists of two connection cards and a network of platinum electrodes positioned in such way that each well in a row is uniformly stimulated. The ESCC may produce a range of outputs based on the stimulation parameters it receives from a commercial pulse generator and can be placed in a standard cell incubator, allowing for long-term stimulation as required for biochemical and molecular biological assays. We show that a 90-min stimulation of C2C12 myotubes at 50 V, 30 ms of pulse duration, and 3 Hz of frequency enhances glucose metabolism and glycogen mobilization while oppositely modulating the activity ratio of glycogen metabolizing enzymes. Thus, we demonstrate that long-term electrical stimulation of C2C12 myotubes with the ESCC results in contractility and metabolic changes, as seen in exercising muscle.
Photobiomodulation (PBM) has been proposed as a potential therapy for spinal cord injury (SCI). We aimed to demonstrate that 810 nm light can penetrate deep into the body and promote neuronal regeneration and functional recovery.
Adult rats underwent a T9 dorsal hemisection, followed by treatment with an 810 nm, 150 mW diode laser (dosage = 1,589 J/cm2). Axonal regeneration and functional recovery were assessed using single and double label tract tracing and various locomotor tasks. The immune response within the spinal cord was also assessed.
PBM, with 6% power penetration to the spinal cord depth, significantly increased axonal number and distance of regrowth (P < 0.001). PBM also returned aspects of function to baseline levels and significantly suppressed immune cell activation and cytokine/chemokine expression.
Our results demonstrate that light, delivered transcutaneously, improves recovery after injury and suggests that light will be a useful treatment for human SCI.
Mitochondrial alterations were monitored after low power green laser (532 nm, 30 mW) irradiation in the case of whole cells (B-14) and isolated mitochondria (from Wistar rat heart). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay products were significantly higher (by 8%) in irradiated B-14 cells as compared to non-irradiated controls. Mitochondrial transmembrane potential of B-14 cells, measured by means of a fluorescent probe 3,3'-dihexyloxacarbocyanine iodide (DiOC6(3)), significantly increased (by 13%) after exposure to green laser irradiation. Another MTT assay was used for isolated mitochondria suspensions in order to examine the effect of green laser irradiation on stimulation of processes related to oxidative phosphorylation. It revealed 31.3%-increase in MTT assay products in irradiated mitochondria as compared to controls. Laser irradiation of isolated mitochondria suspension did not significantly change 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence anisotropy, indicating that mitochondrial membrane fluidity was not affected by laser light. Fluorescence emission spectra of irradiated as well as non-irradiated mitochondria suspensions showed fluorescence maximum at 635 nm, corresponding to emission of Protoporphyrin IX, which was significantly lower (by 20.7%) in irradiated sample.
The present pilot study investigated the analgesic efficacy of light-emitting diode (LED). In view of a standardised and controlled pain reduction study design, this in vivo trial was conducted on experimentally induced delayed-onset muscle soreness (DOMS). Thirty-two eligible human volunteers were randomly assigned to either an experimental (n=16) or placebo group (n=16). Immediately following the induction of muscle soreness, perceived pain was measured by means of a visual analog scale (VAS), followed by a more objective mechanical pain threshold (MPT) measurement and finally an eccentric/concentric isokinetic peak torque (IPT) assessment. The experimental group was treated with infrared LED at one of both arms, the other arm served as control. Irradiation lasted 6 min at a continuous power output of 160 mW, resulting in an energy density of 3.2 J/cm(2). The subjects of the placebo group received sham irradiation at both sides. In post-treatment, a second daily assessment of MPT and VAS took place. The treatment and assessment procedure (MPT, VAS and IPT) was performed during 4 consecutive days. Statistical analysis (a general linear model followed by post hoc least significant difference) revealed no apparent significant analgesic effects of LED at the above-described light parameters and treatment procedure for none of the three outcome measures. However, as the means of all VAS and MPT variables disclose a general analgesic effect of LED irradiation in favour of the experimental group, precaution should be taken in view of any clinical decision on LED. Future research should therefore focus on the investigation of the mechanisms of LED action and on the exploration of the analgesic effects of LED in a larger randomised clinical trial and eventually in more clinical settings.
We investigated whether low-level laser therapy (LLLT) can reduce muscular fatigue during tetanic contractions in rats. Thirty-two male Wistar rats were divided into four groups receiving either one of three different LLLT doses (0.5, 1.0, and 2.5 J/cm2) or a no-treatment control group. Electrical stimulation was used to induce six tetanic muscle contractions in the tibial anterior muscle. Contractions were stopped when the muscle force fell to 50% of the initial value for each contraction (T50%). There was no significant difference between the 2.5 J/cm2 laser-irradiated group and the control group in mean T50% values. Laser-irradiated groups (0.5 and 1.0 J/cm2) had significantly longer T50% values than the control group. The relative peak force for the sixth contraction in the laser-irradiated groups were significantly higher at 92.2% (SD 12.6) for 0.5 J/cm2, 83.2% (SD 20.5) for 1.0 J/cm2, and 82.9% (SD 18.3) for 2.5 J/cm2 than for the control group [50% (SD 15)]. Laser groups receiving 0.5 and 1.0 J/cm2 showed significant increases in mean performed work compared with both the control group and their first contraction values. Muscle damage was indirectly measured by creatine kinase levels in plasma. A distinct dose-response pattern was found in which 1.0 and 2.5 J/cm2 LLLT groups had significantly lower creatine kinase levels than the 0.5 J/cm2 LLLT group and the control group. We conclude that LLLT doses of 0.5 and 1.0 J/cm2 can prevent development of muscular fatigue in rats during repeated tetanic contractions.
There's a fight going on inside all our cells for each breath of air. Nick Lane sheds therapeutic light on the implications for cancer and degenerative diseases.
Redox absorbance changes in living cells (monolayer of HeLa cells)
under laser irradiation at 633, 670, and 820 nm have been studied by the
method of multichannel recording in spectral range 530-890 nm. It has
been found that the irradiation causes changes in the absorption
spectrum of the cells in two regions, near 754-795 nm (maxima at 757,
775, and 795 nm) and near 812-873 nm (maxima at 819, 837, 858, and 873
nm). Changes occur in band parameters (peak positions, width, and
integral intensity). Virtually no changes occur in the red spectral
region and a few changes are recorded in the green region near 556-565
nm. The results obtained evidence that cytochrome c oxidase becomes more
oxidized (which means that the oxidative metabolism is increased) due to
irradiation at all wavelengths used. The results of present experiment
support the suggestion (Karu, Lasers Life Sci., 2:53, 1988) that the
mechanism of low-power laser therapy at the cellular level is based on
the electronic excitation of chromophores in cytochrome c oxidase which
modulates α redox status of the molecule and enhances its
functional activity
The most frequently used mechanism of photon energy conversion in laser medicine is heating. Average heating of irradiated samples occurs with all methods of tissue destruction (cutting, vaporization, coagulation, ablation). Many of these surgical laser techniques are reviewed elsewhere in this book.
The biomodulatory effects of low-level laser therapy (LLLT) function to normalize cellular operations. Research has found that LLLT is capable of decreasing pain and increasing functional ability in numerous musculoskeletal conditions. Excessive energy application can lead to inhibition of cellular processes and delays in the resolution of pathological conditions. Consistent treatment techniques are the key to obtaining reliable and effective results.
We and others have found that physiological/pathological levels of nitric oxide (NO) reversibly inhibit mitochondrial respiration, by binding to cytochrome oxidase in competition with oxygen. We measured O2 and NO concentrations simultaneously using specific electrodes, and showed that nanomolar NO reversibly inhibits oxygen consumption of isolated cytochrome oxidase, mitochondria, synaptosomes, and cells. Oxygen consumption of nerve terminals isolated from brain (synaptosomes) was half inhibited by 270nM NO when the oxygen concentration is 150μM, but half inhibited by 60nM NO when the oxygen concentration was 30μM (a roughly physiological level of oxygen). Cultured astrocytes, activated to express the inducible form of NO synthase produced up to 1μM which strongly and reversibly inhibited cellular respiration via the inhibition of cytochrome oxidase. Mitochondria caused rapid NO breakdown, which may be due to reaction with cytochrome oxidase and/or mitochondrial superoxide. Long-term exposure to NO can cause irreversible damage to mitochondria and cells, which may be mediated by reactive oxygen species or peroxynitrite. We have found that NO reversibly inhibits catalase, with a Ki of 0.3μM NO, and that superoxide dismutase catalyses the reaction of NO and H2O2 to produce peroxynitrite. These reactions might contribute to the cytotoxicity of NO.
Human forearm fibroblasts were irradiated, in vitro, using a Microlaser Medical Pen Unit (Johnson and Johnson) with a wavelength of 860 nm, and an average power output of 50 mW. The irradiation distance and times were adjusted to give energy densities of 2 J/cm2 and 16 J/cm2 respectively. The control unit was adjusted to give a continuous waveform. Fibroblast proliferation and succinic dehydrogenase activity were assessed every 24 hrs over a five day period. The results obtained suggest a relationship between fibroblast proliferation and succinic dehydrogenase activity. At the lower energy density (2 J/cm2), succinic dehydrogenase levels rise with fibroblast proliferation. However, at an energy density of 16 J/cm2, the succinic dehydrogenase levels and fibroblast proliferation appear to be inhibited. These findings agree with previously reported data.
