ArticleLiterature Review

Effect of NASA Light-Emitting Diode Irradiation on Wound Healing

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Abstract

The purpose of this study was to assess the effects of hyperbaric oxygen (HBO) and near-infrared light therapy on wound healing. Light-emitting diodes (LED), originally developed for NASA plant growth experiments in space show promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. In this paper, we review and present our new data of LED treatment on cells grown in culture, on ischemic and diabetic wounds in rat models, and on acute and chronic wounds in humans. In vitro and in vivo (animal and human) studies utilized a variety of LED wavelength, power intensity, and energy density parameters to begin to identify conditions for each biological tissue that are optimal for biostimulation. Results: LED produced in vitro increases of cell growth of 140-200% in mouse-derived fibroblasts, rat-derived osteoblasts, and rat-derived skeletal muscle cells, and increases in growth of 155-171% of normal human epithelial cells. Wound size decreased up to 36% in conjunction with HBO in ischemic rat models. LED produced improvement of greater than 40% in musculoskeletal training injuries in Navy SEAL team members, and decreased wound healing time in crew members aboard a U.S. Naval submarine. LED produced a 47% reduction in pain of children suffering from oral mucositis. We believe that the use of NASA LED for light therapy alone, and in conjunction with hyperbaric oxygen, will greatly enhance the natural wound healing process, and more quickly return the patient to a preinjury/illness level of activity. This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program.

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... 5,6 National Aeronautics and Space Administration (NASA), US Navy and UK military, with their own therapeutic experiments in the 1990s, demonstrated faster recovery post-injuries, enhanced wound healing, angiogenesis and cytoprotection. 7,8 Since three decades, research has demonstrated the efficacy, tolerability and high safety profile of low-level-light-therapies-light-emitting-The various radiations of the electromagnetic spectrum are differentiated according to their wavelength. 1 A smaller segment of this field is observed when white light passes through a prism and refracts separated colored components, known as the light spectrum, constituted of a range from 400 nm to 700 nm of different wavelengths of light visible to the human eye. Infrared (IR) corresponds to wavelengths above the 700 nm nominal edge of red up to 1 millimeter and frequency beneath 400 THz (Figure 1). ...
... 11 NASA experimented the influence of light on astronauts' metabolism, weakened in space in the absence of gravity, evidencing improved wound healing post minor injuries 7 and leading to the equippement of its spaceships with LED panels. 8 Low Level Lasers are non-thermal lasers, known as soft lasers, emitting a coherent, monochromatic polarized light penetrating deeply into tissues, ranging from 400nm to 800nm and 900nm to 940nm for Near-Infrared (NIR). 2 As a comparison, the Helium Neon laser (He-Neon), emitting red at 632nm, has a power output between 1 and 25 milliwatts, whereas the Nd:YAG (neodymium-doped yttrium aluminum garnet) laser, used in cataract surgery, delivers up to 10 watts. Low-Level-Lasers have a significant lower power output requiring longer treatment sessions, ranging in minutes rather than seconds yet, energizing tissues they penetrate rather than cutting or burning them. ...
... Wound healing is maybe the most widely spread application of PBM in dermatology, its effects having been demonstrated at all stages of the healing process. [7][8][9]43,44 A normal wound healing undergoes three distinct phases. At first inflammatory signs in tissues, secretions from lymph and blood vessels, followed by coagulation by thrombokinases activation and fibrin production start the exudation and detersion phase of wound healing. ...
... Regarding phototherapy, light-emitting diode (LED) studies showed an increase in cell growth in vitro, for example in mouse-derived fibroblasts and normal human epithelial cells, and in vivo wound healing time decreased in crew members aboard a submarine (WHELAN et al., 2001). LED phototherapy with combined 660 and 890 nm lights promoted healing of diabetic ulcers in human patients that had been subject to other treatments without success (MINATEL et al., 2009). ...
... There are several light sources that can be used in PDT and/or phototherapy, including lasers, filtered xenon arc, fluorescent lamps and LEDs (WHELAN et al., 2001;BAROLET, 2008;MORTON et al., 2008;SAMPAIO and LOPES, 2015). In the present cases, red LEDs were used. ...
... Wide-field illumination was important in dogs 1 and 3 that had large area wounds, since the equipment had irradiance of 6 LEDs with 130 mW/ cm². The biological effects of LEDs depend on parameters such as dose, intensity, irradiation time, continuous wave or pulsed mode, and pulse patterns (WHELAN et al., 2001;BAROLET, 2008). ...
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The evolution of cutaneous open wounds was evaluated in five client-owned dogs treated with photodynamic therapy (PDT), mediated by methylene blue and phototherapy with light-emitting diodes (LED) as the light source. On the first day of treatment, the wound was irrigated with sterile 0.9% sodium chloride solution, the surface was dried, and 3% solution of hydrogen peroxide soaked for 1 minute. The hydrogen peroxide was mechanically removed and, immediately after, 0.01% methylene blue was used in the wound for five minutes, after which a cluster of red LEDs (650 - 670 nm wavelength, 350 mW power, and irradiance of 200 mW/cm2) was used. Subsequently, single phototherapy sessions, every 48 hours or more, were applied until wound healing. In general, 24J was used for PDT and 12J for phototherapy. In all cases, the cutaneous open wounds treated with PDT associated with phototherapy healed without complications, and it may be considered as a treatment option, especially for extensive lesions.
... In in vitro studies, visible red and near-infra red (NIR) light treatments have been shown to stimulate the proliferation of fibroblasts [6][7][8], endothelial cells [9] and keratinocytes [10], cell types that are essential to wound healing. In vivo-studies, mainly in rats and mice, have investigated the effect on wound healing with varying results [11]. ...
... The horses were deemed healthy after a general clinical examination. The horses were randomly allocated an identity by using numbers (1)(2)(3)(4)(5)(6)(7)(8). The study was performed during March to April. ...
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Background: Light-emitting diodes (LEDs) are commonly used for treating a variety of disorders in horses, including wounds. Despite its claim to shorten healing times, there is a lack of scientific documentation regarding its effects. Objectives: To investigate if treatment with pulsating visible red light (λ≈637 nm) and near-infrared (NIR) light (λ≈956 nm) affects wound healing. Study design: Randomised blinded controlled experimental study. Methods: A circular skin wound (Ø=2 cm) was created on each side of the neck in eight healthy horses. One randomly chosen wound received light treatment and the other served as an untreated control. Treatment duration was 4 minutes and 40 seconds (red light 95 seconds, 2.3 mW/cm2; NIR light 185 seconds, 6.4 mW/cm2) and was performed once daily on day 0-4, 7-11, 14-18 and 21-25. The wounds were photographed and evaluated using digital photoplanimetry on day 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35. The degree of swelling was assessed with diagnostic ultrasound on the same days except the last recording was performed on day 36 instead of 35. Days to total healing was recorded. ANOVA was used for statistical analysis (p<0.05). Results: The wound area (p=0.2-0.9) and degree of swelling (p=0.2-1.0) did not differ between treated and control groups on any day. There was a significant difference (p=0.03) in healing time between control (49.0, 95%CI=35.4-62.6 days) and treated wounds (51.8, 95%CI=38.7-64.8 days). Main limitations: The wounds were treated until day 25 and this study does not investigate the effect of a longer treatment period than 25 days. Conclusions: The results of this study do not indicate any clinically relevant positive effect of pulsating visible red light and NIR light on the healing of experimental skin wounds in horses, compared to no treatment.
... Laser light irradiation has been shown to enhance proliferation and differentiation of a number of human derived cell lines including stem cells 40,41 . Monochromatic light from an LED source, while less extensively studied, has also exhibited the potential to enhance cell proliferation 42 . However, LLLT has also been noted to alter the expression of proteins implicated in progression and invasion of dysplastic cells and this merits further investigation 43,44 . ...
... In an ischemic rat wound model, exposure to red and near infrared light from an LED was associated with differential cellular expression of VEGF and FGF-2 42 . Using the same light source the group observed enhanced wound healing in a range of heterogeneous wounds in an uncontrolled observational study. ...
Article
Light energy is harnessed for therapeutic use in a number of ways, most recently by way of photobiomodulation. This phenomenon is a cascade of physiological events induced by the non-thermal exposure of tissue to light at the near infrared end of the visible spectrum. Therapeutic photobiomodulation has become a highly commercialized interest, marketed for everything from facial rejuvenation to fat loss and diode-based devices are popular in both the clinic setting and for use at home. The lack of regulatory standards makes it difficult to draw clear conclusions about efficacy and safety but it is crucial that we understand the theoretical basis for photobiomodulation so that we can engage in honest dialogue with our patients and design better clinical studies to put claims of efficacy to the test. This article presents a summary of the science of photobiomodulation and examines the differences between laser light, on which much of the preclinical evidence is based and light from diodes which are typically used in a clinical setting.
... Due to Light-Emitting Diode irradiation, a 140-200% increase in cell growth was reported in mouse-derived fibroblasts, rat-derived osteoblasts, and rat-derived skeletal muscle cells As to normal human epithelial cells they grew by 155 to 171% [24]. All details of these experiments are summarized in Table 2. ...
... LLLT enhanced a significant increase in the initial number of stem cells [25]. Likewise, LLLT could improve the viability and proliferation rate of healthy and osteoporotic bone marrow Mesenchymal Stem Cells (MSC) [26].Interestingly, diode laser is a HaCAT epithelial cells treated synthesized twice the amount of collagen than that of the control cells [24] Whelan relevant approach for the preconditioning of MSC prior cell transplantation [28]. LLLT on adipose-derived MSC resulted in rapid bone formation [28]. ...
Article
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Background Oral mucositis (OM) is a severe complication cancer patients undergo when treated with chemoradiotherapy. Photobiomodulation (PBM) therapy also known as low-level laser therapy has been increasingly used for the treatment of such oral toxicity. The aim of this review is to discuss the mechanisms of photobiomodulation (PBM) regarding OM prevention and treatment, and more precisely to focus on the effect of PBM on tumor and healthy cells. Methods MEDLINE/PubMed, and google scholar were searched electronically. Selected studies were focusing on PBM effects on tumor and healthy cells. Results PBM interactions with the tissue and additional mechanism in OM therapy were detailed in this review. Moreover, this review highlighted a controversy about the carcinogenic effect of PBM. Indeed, Many studies reported that PBM could enhance malignant cell proliferation; suggesting that PBM would have no protective effect. In addition to acting on cancer cells, PBM may damage healthy cells. Conclusion More prospective studies are needed to assess the effect of PBM on cancer cells in order to improve its use for OM prevention and treatment.
... Light-emitting diodes (LEDs) have been shown to be a safe, efficient, lightweight, and less-expensive alternative for photobiomodulation when compared to LLLT [12,13]. LEDs are compact and light and require low energy, and they can be arranged in flat clusters allowing for the treatment of different anatomic areas [14]. ...
... This makes some authors suggest that laser light is more effective than LED; however, it is well stablished that the coherence of laser light is lost when the light hits the superficial tissue layers [24,25]. Moreover, previous studies showed that LED and lasers at the same wavelengths have similar tissue effects such as angiogenesis, collagen stimulation, tissue repair, and analgesia [12,22,23]. Thus, LEDT has been suggested as a low cost, secure, light, and compact alternative for the laser systems. ...
Article
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Purpose The objective of the present study was to compare the efficacy of photobiomodulation with low-level laser therapy (LLLT) or light-emitting diode therapy (LEDT) devices for the prevention and treatment of oral mucositis in pediatric patients diagnosed with acute lymphoblastic leukemia undergoing chemotherapy with high doses of methotrexate (MTX). Methods Eighty patients were randomly divided into two groups: LLLT and LEDT. Both protocols were applied with the same energy and radiant exposure. The protocols started in the beginning of high doses MTX and finished when the patients were discharged from the hospital or there was oral mucositis resolution. The oral mucositis was assessed during each session in accordance to the World Health Organization (WHO) score. The patients’ self-assessed pain was scored on a visual analog scale (VAS). Results The incidence of oral mucositis was similar to LLLT and LEDT, 10% and 12.5%, respectively. Both groups required the same number of days to reach score of zero for mucositis and pain (p > 0. 05), and there was no significant difference in mean VAS between the groups. Conclusions These findings suggest that LEDT has similar effects to LLLT to avoid and treat oral mucositis. Brazilian Clinical Trial Registry with #U1111-1221-5943
... Likewise the regrowth of hair cells or other cochlear structures [74] is an extremely challenging problem, although simply reconnecting peripheral processes that have been damaged while leaving intact hair cells [75] may be more manageable in the foreseeable future. While not a drug, near infrared light has been shown to promote tissue healing [76], helping reduce the extent of hearing loss following cochlear stress [77] and has been proposed as an approach that might also enhance the cochlea's ability to survive the traumas of electrode array insertion. ...
... The photostimulatory effect has been proven to promote cell activity, such as photojuvenation and wound healing. 50 The optimal wavelengths for photomodulation are 680, 730, and 880 nm, 51 which match the wavelengths of IPL treatment. It was suggested that IPL may help improve the MG microstructure. ...
Article
Objectives: To evaluate recent studies on available therapies for meibomian gland dysfunction (MGD). Methods: A literature search on recent publications, within the last five years, concerning treatment options for MGD was performed. Results: A total of 35 articles were reviewed after curation by the authors for relevance. In general, all modalities of treatments were shown to have clinical efficacy in alleviating dry eye signs and symptoms, although the extent of improvement and persistency of outcomes varied between the different treatments. Evidence from published studies demonstrate that thermal pulsation produces the longest lasting effect per treatment, but it also incurs the highest per-treatment cost. Reusable methods for warm compress with lipid/semi-fluorinated alkane-containing eye drops are recommended as first-line treatment for mild-to-moderate dry eye patients, because this option is most technically feasible and cost-effective in clinical practice. Intense pulsed light (IPL) therapy and thermal pulsation may be suitable as second line for patients unresponsive to warm compress therapy; however, their respective limitations need to be considered. For refractory MGD with features of periductal fibrosis or severe blepharitis, supplementary treatment with meibomian gland probing or oral antibiotics may be used. Conclusions: All eight forms of treatments, including self-applied eyelid warming, thermal pulsation, IPL, MG probing, antibiotics, lipid-containing eye drops, and perfluorohexyloctane, were effective against MGD, although with varying extent of clinical improvements. A better understanding on the mechanisms of actions may guide physicians to make better treatment decisions targeting the root causes.
... It also increased the growth of normal human epithelial cells by 155-171%. In ischemic rat models, wound size decreased up to 36% after PBM therapy (PBMT) in conjunction with hyperbaric oxygen [9]. In another in vitro study, PBMT inhibited cyclooxygenase enzyme and prostaglandin E 2 release, indicating PBMT might have potential as an anti-inflammatory tool [10]. ...
Article
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This study aimed to evaluate the effect of photobiomodulation (PBM) for prevention of radiodermatitis in an irradiated mouse model and compare the efficacy of PBM using 633- or 830-nm wavelengths. Irradiated mice were randomly distributed into three groups: A (633 nm), B (830 nm), and C (without PBM). On post-irradiation days 7 and 21, we compared acute damage and recovery in treated skin samples to non-irradiated skin using H&E, Masson’s trichrome, anti-CD45 and PCNA immunohistochemistry, and a TUNEL assay. Grade 3 radiodermatitis was evident only in group C. Compared with that in group C, the skin in groups A and B had significantly less epidermal hyperplasia, inflammatory cell infiltration, and thinner dermis on day 7 and less inflammatory cell infiltration, fewer apoptotic cells, and thinner dermis on day 21. However, there was no significant difference between groups A and B. This study indicates PBM could prevent severe radiodermatitis by reducing epidermal and dermal damage, inflammation, and apoptosis. There was no difference in PBM efficacy between the 633- and 830-nm wavelengths.
... PBM has been clinically applied for treatment of wound healing [189,190], muscle injury [191], retinal diseases [192] and pain management [193]. PBM has also been studied as a potential therapy for various neurological diseases such as neurodegenerative diseases, stroke and brain injury [194]. ...
Chapter
Spinal cord injury (SCI) is a devastating trauma that often leads to a permanent loss of motor and sensory functions, pain, and spasticity. A functional repair of injured tissue in the adult central nervous system remains a major issue for current biomedical research and its advancing clinical translation. Regenerative medicine, together with tissue engineering and various interdisciplinary methods, may offer new approaches to reduce neuronal death, glial scars at the injury site, and induce axonal regeneration. In this review we introduce SCI, its pathophysiology, available experimental models, and behavioral testing, which have been used for its further study. We also provide a comprehensive overview of selected experimental approaches based on cell transplantation, antioxidative treatment, laser therapy, biomaterial scaffolds, and their combinations. Finally, we consider the future direction of spinal neuromodulation research such as electrical stimulation or molecular manipulation, which could overcome molecular barriers inhibiting axonal growth to promote regeneration.
... LED is a non-coherent and non-collimed light source that is suggested for healing on several tissues by the National Aeronautics and Space Administration (NASA) [16]. Various studies have demonstrated that LED presents good results for those diseases that are characterized by inflammation [17,18]. Although the positive effects of LED, its mechanisms of action are poorly understood. ...
Article
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The aim of this study was to evaluate the in vivo response of red light-emitting diode (LED) on acute lung injury (ALI) in a sepsis model in rats. Twenty rats were randomly allocated into two experimental groups (n=10): Control Sepsis Group (CS); sepsis and red LED group (SRL). The anterior region of the trachea and ventral regions of the chest (below the ribs), bilaterally were irradiated daily for two consecutive days, starting immediately after the surgery using red (630 nm) LED. The histological results showed that in red LED treated group presented a modulation of the lung inflammatory process, less intense alveolar septum thickening and decrease of the inflammatory cells. Moreover, LED significantly reduced the lung injury score and increased interleukin type 10 (IL-10) protein expression compared SG. These results suggest that LED was efficient in attenuating ALI in a sepsis model in rats by reducing inflammatory cells into lung tissue and enhancing the anti-inflammatory cytokine production.
... The LED therapy device used was WARP 10 LED (Quantum Devices Inc, Barneveld, NY) with the following parameters: 50 mW/cm 2 of photon flux (power) in the near-IR portion of the electromagnetic spectrum (650-950 nm), which produces 4 Joules/dose in 80 seconds. 5,6 The data related to the patients' age and sex in both groups were collected at the beginning of the study, and the data concerning the wound surface area were measured before the study (pre) and after 24 treatment session (post) by using wound surface area tracing double-sterilized transparent 1-cm grid paper (Figure 2), calculated by computerized method using magnetic lasso tool in Photoshop CS3 application ( Figure 3). ...
Article
Chronic nonhealed wound after below-knee amputation is a serious problem that is faced by the health care team; therefore, there is a need to find an adjuvant therapy to address this problem. The aim of the study is to evaluate the therapeutic efficacy of light-emitting diode (LED) irradiation on chronic nonhealed wound after below-knee amputation using a digitalized method of evaluation by Adobe Photoshop CS5 aided by magnetic lasso tool. Thirty patients with chronic nonhealed wound (≥4 weeks) after below-knee amputation were randomly divided into 2 equal groups, with 15 participants in each. Group A received the LED irradiation for 24 sessions (3 sessions per week) in addition to the standard medical treatment, and the second experimental group (group B) received the standard medical treatment for 8 weeks. Methods of evaluation included the wound surface area: for tracing the wound perimeter using a computerized software. Results showed that both LED irradiation therapy and standard medical treatment were effective in healing the chronic nonhealed wound, but the LED was more effective than standard medical treatment alone. A clear improvement in the results of wound healing surface area was found in group A, with an improvement percentage of 50.63%, when compared with group B, which used the standard medical treatment alone, with an improvement percentage of 43.96%.
... Light energy densities between 0.5 and 4 J/cm 2 are more effective in stimulating stem cell growth [31][32][33][34]. The range of LLLI or LED sources is typically 1-500 mW [35,36]. Studies have confirmed the positive effects of interval exposure during PBM treatment [28]. ...
Article
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This study aimed to evaluate the effects of low-energy blue LED irradiation on the osteogenic differentiation of stem cells from the apical papilla (SCAPs). SCAPs were derived from human tooth root tips and were irradiated with 0 (control group), 1 J/cm2, 2 J/cm2, 3 J/cm2, or 4 J/cm2 blue light in osteogenic induction medium. Cell proliferation was analyzed using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. Osteogenic differentiation activity was evaluated by monitoring alkaline phosphatase (ALP), alizarin red staining, and real-time polymerase chain reaction (RT-PCR). The results of the MTT assay indicated that SCAPs in the LED groups exhibited a lower proliferation rate than those in the control group, and there were statistically differences between the 2 J/cm2, 3 J/cm2, and 4 J/cm2 groups and the control group (P < 0.05). The results of the ALP and alizarin red analyses showed that blue LED promoted osteogenic differentiation of the SCAPs. And 4 J/cm2 blue light upregulates the expression levels of the osteogenic/dentinogenic genes ALP, dentin sialophosphoprotein (DSPP), dentin matrix protein-1 (DMP-1), and osteocalcin (OCN) in SCAPs. Our results confirmed that low-energy blue LED at 1 J/cm2, 2 J/cm2, 3 J/cm2, and 4 J/cm2 could inhibit the proliferation of SCAPs and promotes osteogenic differentiation of SCAPs. Further in vitro studies are required to explore the mechanisms of the effects by low-energy blue LED.
... It was also effective in increasing the collagen generation in aged animals in various stages of the tissue regeneration process [30]. LED was reported to promote cell growth by approximately 140-200% in the cases of fibroblasts, osteoblasts, and skeletal muscle cells in mice, and by approximately 155-171% in human epithelial cells [31]. Accordingly, the involvement of PBMT in tissue reformation was verified [32]. ...
Article
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Pressure ulcer is a disease that has been increasing rapidly worldwide in recent years following the growing elderly population. However, its diagnoses and treatments still depend on the naked eye and traditional drug treatments, respectively. In this study, we examined the effects of the pressure ulcer-induced regions based on impedance measurements and skin electrical signals, and its treatment efficacy was verified using photobiomodulation therapy. The light used in this therapy was a light emitting diode light (660 nm), and it was verified to enhance antioxidant capacity in the enzyme-based antioxidation process. An examination of the angiogenesis efficacy based on wound healing activity and tube formation activation at the cell level confirmed that photobiomodulation therapy accelerated wound healing and angiogenesis. When the treatment effect of the therapy was evaluated with a rat animal model of pressure ulcer, the region affected by the pressure ulcer and the infiltration of inflammatory cells were significantly reduced by photobiomodulation therapy. The diagnosis using skin impedance measurement showed differences in the region affected by the pressure ulcer. The results of this study confirmed the diagnosis based on the impedance and treatment efficacy of photobiomodulation therapy and the treatment of pressure ulcer. The use of photobiomodulation therapy in conjunction with the existing treatment methods is expected to improve the efficiency of the pressure ulcer treatment.
... Concerning LED, when the first one was developed in 1998 by Harry Whelan and his group at the NASA space medicine laboratory [8], this technology had some characteristics that diverge them from laser devices. While LED are noncoherent and quasimonochromatic light sources [9] based on the phenomenon of electroluminescence of semiconductor materials [10], laser emits, in a stimulated manner, a monochromatic, and coherent light beam of low divergence [11]. Besides that, it is important to quote that those different properties would still photoactivate cells without causing heat changes or damage. ...
Article
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This study evaluated the effects of light-emitting diode (LED) on mesenchymal stem cells (MSCs). An electronic search was conducted in PubMed/MEDLINE, Scopus, and Web of Science database for articles published from 1980 to February 2020. Ten articles met the search criteria and were included in this review. The risk of bias was evaluated to report quality, safety, and environmental standards. MSCs were derived from adipose tissue, bone marrow, dental pulp, gingiva, and umbilical cord. Protocols for cellular irradiation used red and blue light spectrum with variations of the parameters. The LED has been shown to induce greater cellular viability, proliferation, differentiation, and secretion of growth factors. The set of information available leads to proposing a complex signaling cascade for the action of photobiomodulation, including angiogenic factors, singlet oxygen, mitogen-activated protein kinase/extracellular signal-regulated protein kinase, Janus kinase/signal transducer, and reactive oxygen species. In conclusion, although our results suggest that LED can boost MSCs, a nonuniformity in the experimental protocol, bias, and the limited number of studies reduces the power of systematic review. Further research is essential to find the optimal LED irradiation parameters to boost MSCs function and evaluate its impact in the clinical setting.
... Considerando que esse ultimo prazo (8 semanas) se tratou se uma ferida com complicações sistêmicas, pois se tratava de úlcera em pé diabético, justifica-se o tempo mais prolongado de cicatrização . Os efeitos cicatrizantes começaram a ser demonstrados precocemente, relatando-se diminuição do eritema nas primeiras 48 horas em pacientes no pós operatório (Whelan et al., 2001) e diminuição dos sintomas de dor em pacientes tratados com LED (Rimulo et al., 2011). ...
Article
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A reparação de feridas constitui um processo complexo, que envolve fatores externos e internos do tecido local, seguindo fases que vão desde a proliferação celular, passando pela angiogênese até o fechamento total da ferida com a reepitelização. A quitosana e a fototerapia por luz emitida por diodo (LED– Light Emiting Diode) são duas terapias que estimulam o reparo tecidual. O presente estudo teve como objetivo realizar revisão bibliográfica acerca dos efeitos cicatricial do LED e da Quitosana de forma isolada e associada. Uma busca na literatura foi realizada utilizando uma variedade de fontes, incluindo base de dados on line. A busca em bancos de dados possibilitou a seleção de 15 artigos sobre o efeito do LED na cicatrização e 17 artigos sobre os efeitos cicatrizantes da quitosana. Não foram encontrados nesta revisão artigos que relatassem a associação dos dois procedimentos na cicatrização. Os artigos analisados mostram os efeitos positivos e isolados do LED e de compostos à base de quitosana na aceleração do processo cicatricial. Observou-se falta de padronização nos estudos quanto as variáveis analisadas. Sugerem-se novos estudos que avaliem a eficácia da associação dos dois procedimentos: LED e Quitosana.
... The mechanical effects induced by ultrasound transducers can promote tumor necrosis by inducing the appropriate power and frequency of the transmitted sources [24][25][26][27]. Tumor cell structures and functions exposed to low-frequency ultrasound can be deformed, thus resulting in cell damage, necrosis, proliferation, migration, etc. [28][29][30]. ...
Article
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Light emitting diode (LED) and ultrasound have been powerful treatment stimuli for tumor cell growth due to non-radiation effects. This research is the first preliminary study of tumor cell suppression using a macro-lens-supported 460-nm LED combined with high-frequency ultrasound. The cell density, when exposed to the LED combined with ultrasound, was gradually reduced after 30 min of induction for up to three consecutive days when 48-W DC, 20-cycle, and 50 Vp-p sinusoidal pulses were applied to the LEDs through a designed macro lens and to the ultrasound transducer, respectively. Using a developed macro lens, the non-directional light beam emitted from the LED could be localized to a certain spot, likewise with ultrasound, to avoid additional undesirable thermal effects on the small sized tumor cells. In the experimental results, compared to LED-only induction (14.49 ± 2.73%) and ultrasound-only induction (13.27 ± 2.33%), LED combined with ultrasound induction exhibited the lowest cell density (6.25 ± 1.25%). Therefore, our measurement data demonstrated that a macro-lens-supported 460-nm LED combined with an ultrasound transducer could possibly suppress early stage tumor cells effectively.
... This LED was 5 orders of magnitude more powerful than the then-current LEDs, and very narrowband, quasimonochromatic, with more than 98% of the photons at the rated wavelength offering laser-like target selectivity. Finally another light source, easier to manage and less-expensive than the laser diode, became available to researchers and clinicians, and Low Level Laser Therapy became Low Level LIGHT Therapy [8], but still LLLT, proving very effective in wound healing [9]. Low level light therapy with LEDs (LED-LLLT) had finally arrived as a valid medical tool. ...
... Most photomedical research has been conducted using rigid LED 39,40 , rigid OLED [36][37][38] , and rigid QLED 41 light sources. Recently, however, research has been conducted on patches for wound healing that utilize the advantages of conformable OLEDs 21,35 , and photomedical studies have also been conducted using conformable QLEDs 42 . ...
Article
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Free-form optoelectronic devices can provide hyper-connectivity over space and time. However, most conformable optoelectronic devices can only be fabricated on flat polymeric materials using low-temperature processes, limiting their application and forms. This paper presents free-form optoelectronic devices that are not dependent on the shape or material. For medical applications, the transferable OLED (10 μm) is formed in a sandwich structure with an ultra-thin transferable barrier (4.8 μm). The results showed that the fabricated sandwich-structure transferable OLED (STOLED) exhibit the same high-efficiency performance on cylindrical-shaped materials and on materials such as textile and paper. Because the neutral axis is freely adjustable using the sandwich structure, the textile-based OLED achieved both folding reliability and washing reliability, as well as a long operating life (>150 h). When keratinocytes were irradiated with red STOLED light, cell proliferation and cell migration increased by 26 and 32%, respectively. In the skin equivalent model, the epidermis thickness was increased by 39%; additionally, in organ culture, not only was the skin area increased by 14%, but also, re-epithelialization was highly induced. Based on the results, the STOLED is expected to be applicable in various wearable and disposable photomedical devices.
... The fluorescent technology of the LumiHeal gel is based on the ability of particular molecules (chromophores) to capture light emitted by a blue LED lamp and then to convert it into a different and wider emission spectrum in the visible spectrum (fluorescence) with a longer wavelength and therefore with lower energy 2 (wavelength range emitted: 532-615 nm). Several studies have shown that the most effective wavelengths in penetrating the skin and promoting healing are those of blue, green, yellow, and orange; each wavelength corresponds to a precise biological effect (Table 1) [13][14][15] ; the main feature of the LumiHeal system is precisely that of maximizing the therapeutic effect of photobiomodulation by causing the wound to be irradiated simultaneously by several different wavelengths. The progression of the process is visually controllable, thanks to the color variations of the gel in the various phases: at the time of application, the gel appears orange; the activated gel appears intense yellow and once exhausted it turns pink transparent. ...
Article
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Background: Chronic ulcers represent a challenge for healthcare professionals and a large expense for national health care systems for their difficulty in achieving complete healing and for their high incidence of recurrence. With the progressive aging of the general population, the incidence of these injuries will only increase, further affecting the public health budget, hence the need to find new strategies for their management. The purpose of this study was to share the experience of the Complex Operational Unit of Plastic Surgery of the University Hospital of Padua with fluorescent light energy therapy, outlining its role in the treatment of chronic ulcers in the daily use outside the previous EUREKA study. Methods: In this case series study, we enrolled 15 patients with chronic ulcers of any etiology between January 2018 and July 2019 and we treated them using fluorescence light energy. We evaluated efficacy and safety endpoints reporting data in excel files completed by medical staff during the study. Results: The study confirms the effectiveness of fluorescent light energy inducing chronic ulcer healing, regardless of etiology, or at least preparing the lesions for a skin graft closure surgery. The system showed a low rate of complications established by patient adherence to treatment. Patients also reported a reduction in pain both at home and during outpatient dressings. Conclusion: Based on our experience, fluorescent light energy shows an excellent safety and efficacy profile in chronic ulcers no more responsive to traditional dressings and/or surgery.
... 5 Next through their NASA LED wound healing studies, Whelan et al. showed that useful bio-reactions could be achieved by the use of LEDs without any heat or damage through their ability of cellular photoactivation. 10 LPT is a relatively new phenomenon and started appearing regularly in the literature only since 2001, where focus was on the redand near-infrared radiation and their various effects at the physiological levels. 5 FDA deemed NIR -LED light therapy to be a nonsignificant risk for approved use in humans 11 and US photobiologist, Kendric C Smith renamed low level laser therapy as 'Low level light therapy' (LLLT) to encompass LED energy. ...
Article
BACKGROUND Photobiomodulation is an emerging area of medical and dental science that has gained attention in numerous clinical fields with the advent of new generational light - emitting diodes (LEDs), as evident in the extent of published scientific literature in recent years. The rationale behind LED - mediated photobiomodulation therapy (LPT) is that at certain biologically active wavelengths, LEDs have shown to have therapeutic effects at the cellular and subcellular levels and are an efficient alternative photon source after lasers, along with their numerous benefits. Subsequent to favourable in-vitro, animal and recently human clinical trials, considerable attention has been garnered towards the promising applications and the integration of LPT with traditional therapeutic protocols, including in orthodontics. Originally started and accepted as a modality in acceleration of tooth movement, pain management and increasing the bone remodelling rate and quality, the advancements in this therapeutic technology have created new avenues in the treatment of temporomandibular disorders, root resorption, bone consolidation during maxillary expansion and distraction osteogenesis, as well as for improvement in miniscrew stability. Since it is non-invasive, easy to perform and user friendly with reported efficacy, an established consensus of wavelengths and parameters with respect to guidance for clinical use will go a long way in enabling the successful achievement of numerous objectives. This review article of published research intends to evaluate the adjunctive applications of LPT within orthodontic treatment at several levels along with the underlying mechanism, parameters and reported outcomes. KEY WORDS Photobiomodulation Therapy, Light Emitting Diodes, LED - Mediated Phototherapy, Low Level Light Therapy, NIR-LED, Light Accelerated Orthodontics
... 6 Exposure to 670 or 726 nm LEDs red light was reported to decrease the healing time in chronic ischemic ulcers in rats. 7,8 Therefore, achievement of novel red/far-red sources would significantly promote the development of plant cultivation and phototherapy. ...
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Emerging phototherapy in a clinic as well as plant photomorphogenesis call for efficient red/far-red light resources to target and/or actuate the interaction of light and living organisms. Rare-earth doped phosphors are generally promising candidates for efficient light-emitting diodes but still bear lower quantum yield for the far-red components, potential supply risks, and high cost issues. Thus, design and preparation of efficient non-rare-earth activated phosphors becomes extremely important and arouses great interest. Fabrication of Cr3+-doped Na3AlF6 phosphors significantly promotes the potential applications by efficiently converting blue excitation light of a commercial InGaN chip to far-red broadband emission in the 640-850 nm region. Action response of phototherapy (~ 667-683 nm; ~ 750-772 nm) and that of photomorphogenesis (~ 700-760 nm) are well overlapped. Based on the temperature-dependent steady luminescence and time-resolved spectroscopies, energy transfer models are rationally established by means of the configurational coordinate diagram of Cr3+ ions. An optimal sample of Na3AlF6: 60% Cr3+ phosphor generates a notable QY of 75 ± 5%. Additionally, an InGaN LED device encapsulated using Na3AlF6: 60% Cr3+ phosphor was fabricated. The current exploration will pave a promising way to engineer non-rare-earth activated optoelectronic devices for all kinds of photobiological applications.
... In this study, we used DCFH probe to detect ROS, and the green fluorescence value was proportional to the level of ROS [6]. ROS is the normal metabolite of redox reactions in the cell, mainly coming from the mitochondrial respiratory chain, ROS is related to mitochondrial oxidative phosphorylation, apoptosis, immunity, and inflammation [25][26][27][28][29][30]. In this study, HGFs were stimulated by 16 µg/mL LPS, the production of intracellular ROS increased. ...
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Periodontal disease is the most common oral chronic inflammatory disease in humans. Recent studies have indicated that red light Photobiomodulation (PBM) could inhibit cell inflammation effectively, but the effect of different doses of PBM on the treatment of inflammation has to be improved. Thus, this study was aimed to investigate the effects of various doses of PBM (630 ± 30 nm, (1) 5 mW/cm2, 1 J/cm2, 200 s; (2) 5 mW/cm2, 3 J/cm2, 600 s; (3) 5 mW/cm2, 9 J/cm2, 1800 s; (4) 5 mW/cm2, 18 J/cm2, 3600 s; (5) 5 mW/cm2,36 J/cm2, 7200 s) on the anti-inflammatory response of human gingival fibroblasts. Our results suggested that PBM (630 ± 30 nm) with doses of 18 J/cm2 and 36 J/cm2 could significantly inhibit the production of inflammatory cytokines such as Prostaglandin E2 (PGE2) and IL-8, presumably due to the fact that a high dose of PBM treatment could reduce intracellular Reactive oxygen species (ROS) in human gingival fibroblasts, thus reducing the expression of COX-2 enzyme. In addition, it was found that treatment with different doses of PBM (630 ± 30 nm) did not result in reduced mitochondrial membrane potential and mitochondrial dysfunction in human gingival fibroblasts. Our study provides a theoretical reference for the selection of PBM parameters and the application of PBM in the clinical treatment of periodontitis.
... The levels of growth factors did not show a significant difference in the comparison between control and irradiated membranes. However, some studies have shown that laser therapy is able to promote the increase or biomodulation of growth factors, such as VEGF, FGF-2, EGF, PDGF, and TNFα, and TGF-ß [28][29][30] . However, in rat calvarial defects filled with xenograft and covered with the collagen membrane, the photobiomodulation provided a greater amount of bone volume only during the first 14 days after surgery 14 . ...
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Purpose: To evaluate the low-level laser therapy (LLLT) on the membrane induced by the Masquelet technique in rabbits. Methods: Twelve Norfolk rabbits at approximately 3 months of age were used. A 1-cm segmental defect was induced in both radii, which were filled with polymethylmethacrylate cylinder. LLLT was used postoperatively in the bone defect of one of the forelimbs every 48 hours for 15 days. Six rabbits were euthanatized on third and sixth postoperative weeks. Results: In both forelimbs, radiographs showed new bone growth from radius cut ends on the third postoperative week and more advanced stage on the sixth postoperative week. Ultrasound showed induced membrane one week after the surgery. Histologically, there were no significant differences in the semi-quantitative score of inflammation intensity, total number of blood vessels, bone metaplasia, and collagen. The average thicknesses were 2,050.17 and 1,451.96 μm for control membranes and 2,724.26 and 2,081.03 μm for irradiated membranes, respectively, on third and sixth postoperative weeks. Vascular endothelial growth factor A (VEGF-A) and platelet derived growth factor (PDGF) expression were present in the induced membranes of control and irradiated forelimbs, but there was no significant difference. Conclusions: Based on assessment methods, it was not possible to demonstrate the effect of LLLT on the induced membrane.
... 8,9 Photobiomodulation (PBM), also known as lowlevel laser therapy, is a noninvasive treatment and has been widely used in clinics to accelerate the repair of tissues in human beings. [10][11][12] Many studies have reported that PBM mediated by laser plays a positive role in wound healing of DFU patients through promoting cell proliferation of keratinocyte and¯broblasts, neovascularization, and a reduction of in°ammation. 13 In recent years, the lightemitting diodes (LEDs)-mediated PBM is going to provide DFU patients with a more feasible and lower-cost therapeutic option. ...
Article
Photobiomodulation (PBM) promoting wound healing has been demonstrated by many studies. Currently, 630 nm and 810 nm light-emitting diodes (LEDs), as light sources, are frequently used in the treatment of diabetic foot ulcers (DFUs) in clinics. However, the dose–effect relationship of LED-mediated PBM is not fully understood. Furthermore, among the 630[Formula: see text]nm and 810[Formula: see text]nm LEDs, which one gets a better effect on accelerating the wound healing of diabetic ulcers is not clear. The aim of this study is to evaluate and compare the effects of 630[Formula: see text]nm and 810[Formula: see text]nm LED-mediated PBM in wound healing both in vitro and in vivo. Our results showed that both 630[Formula: see text]nm and 810[Formula: see text]nm LED irradiation significantly promoted the proliferation of mouse fibroblast cells (L929) at different light irradiances (1, 5, and 10[Formula: see text]mW/cm[Formula: see text]. The cell proliferation rate increased with the extension of irradiation time (100, 200, and 500[Formula: see text]s), but it decreased when the irradiation time was over 500[Formula: see text]s. Both 630[Formula: see text]nm and 810[Formula: see text]nm LED irradiation (5[Formula: see text]mW/cm[Formula: see text] significantly improved the migration capability of L929 cells. No difference between 630[Formula: see text]nm and 810[Formula: see text]nm LED-mediated PBM in promoting cell proliferation and migration was detected. In vivo results presented that both 630[Formula: see text]nm and 810[Formula: see text]nm LED irradiation promoted the wound healing and the expression of the vascular endothelial growth factor (VEGF) and transforming growth factor (TGF) in the wounded skin of type 2 diabetic mice. Overall, these results suggested that LED-mediated PBM promotes wound healing of diabetic mice through promoting fibroblast cell proliferation, migration, and the expression of growth factors in the wounded skin. LEDs (630[Formula: see text]nm and 810[Formula: see text]nm) have a similar outcome in promoting wound healing of type 2 diabetic mice.
... FR/NIR light is produced from a laser or a lightemitting diode (LED), and its therapeutic qualities have been confirmed [121]. FR/NIR light therapy has been widely used over the years, including for increasing cerebral blood flow (CBF) [122,123], augmenting brain energy metabolism [124,125], improving the antioxidant capacity [126], promoting cell growth [127], and improving the reparative ability of cells [128]. In the ophthalmic field, FR/NIR also had uneventful grades. ...
Article
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Introduction: The aim of this article was to comprehensively review the relationship between light exposure and myopia with a focus on the effects of the light wavelength, illuminance, and contrast on the occurrence and progression of myopia. Methods: This review was performed by searching PubMed data sets including research articles and reviews utilizing the terms "light", "myopia", "refractive error", and "illuminance", and the review was concluded in November 2021. Myopia onset and progression were closely linked with emmetropization and hyperopia. To better elucidate the mechanism of myopia, some of the articles that focused on this topic were included. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors. Results: The pathogenesis and prevention of myopia are not completely clear. Studies have provided evidence supporting the idea that light could affect eye growth in three ways. Changing the corresponding conditions will cause changes in the growth rate and mode of the eyes, and preliminary results have shown that FR/NIR (far red/near-infrared) light is effective for myopia in juveniles. Conclusion: This review discusses the results of studies on the effects of light exposure on myopia with the aims of providing clues and a theoretical basis for the use of light to control the development of myopia and offering new ideas for subsequent studies.
... Green light (peaked at 560 nm) is thought to have a positive effect on the migratory movement of stem cells [23]. And red light (peaked at 630 nm) is mostly used for tissue wound healing, skin inflammation and arthritis treatment [24][25][26][27]. Red light induces differential alterations in 76 genes in wounds treatment [28]. ...
Article
Photobiomodulation (PBM) has emerged as an alternative therapy involved in modulating a variety of biological effects. In this study, we verified whether PBM can affect cardiac physiological activity in mice through noninvasive irradiation using light-emitting diodes at a wavelength of 630 nm (LED-Red). We found that the PBM involved in regulating the repair of injured myocardium is wavelength-limited. LED-Red caused cardiomyocytes (CMs) that had exited the cell cycle to divide and proliferate again, and the cell proliferation ratio increased significantly with the accumulation of intracellular photopower. In addition, LED-Red promoted myocardial revascularization and myocardial regeneration, reduced the area of fibrosis in mice with myocardial infarction (MI), and thus improved cardiac contractile function. In regard to the mechanism, miRNA sequencing analysis showed that low-power LED-Red irradiation could induce differential changes in miRNAs in CMs. Among them, miR-136-5p was identified as a cardiac photo-sensitive miRNA and was obviously inhibited after stimulation, which produced a proliferation-promoting effect on CMs. Subsequent luciferase reporter assays confirmed the involvement of Ino80 as a binding target of miR-136-5p in the regulatory process of CM proliferation. Similarly, LED-Red irradiation elevated intracellular Ino80 expression. After knockdown of Ino80, the proliferation-promoting effect of LED-Red on CMs was inhibited. Collectively, this study demonstrates that LED-Red can promote CM proliferation by inhibiting cardiac photo-sensitive miRNA- miR-136-5p expression through targeting Ino80. The findings provided a new potential strategy for the treatment of ischemic cardiomyopathy (ICD).
... The classes indicate the potential danger to the eye from the radiation. In 1999, Whelan et al 6 presented the medical applications of LEDs for use on the NASA space station. In 2001, the FDA approved the first cold laser for treating pain. ...
Article
Triboluminescence (TL) refers to the luminescence phenomenon at the material surface under the action of pressure or shear. This fascinating phenomenon can directly convert mechanical energy into light emission without the need for other auxiliary components, which attracts more and more researchers to conduct research in different wavelength ranges, such as x-ray, ultraviolet, visible light, terahertz. However, there have been few reports on the study of the near-infrared range, which is very important in the integrity of the triboluminescence research. In this research, we found the phenomenon that NIR light with a wavelength from 800nm to 1000nm was generated by friction between solid metals and quartz crystal. Analysis of the cross-section of quartz disk after friction revealed that the TL phenomenon had a strong relationship with the doping of the metal grains into the silica. The density functional theory (DFT) and X-ray photoelectron spectroscopy were also conducted to further identify the results. We infer that such light emission arises from the implantation of metal grains into the surface of the quartz, which forms a metal-insulator junction with amorphous silica. And electron transition between the metal and insulator followed by a transition at the center of the defects causes near-infrared light emission. Our research reveals the infrared luminescence behavior from a different perspective, the transfer of materials, and perhaps deepens the understanding of the near-infrared emission mechanism.
Article
To fight against the counteractive triplet–triplet annihilation and vibrational deactivation faced by low bandgap phosphorescent emitters, aggregation-induced phosphorescent enhancement (AIPE)-active deep-red and NIR emissive iridium(III) complexes are designed by suitably anchoring electron-withdrawing substituents such as -phenyl (Ir2), -ethyl ester (Ir3), and -trifluoromethyl (Ir4) groups on the N-coordinating quinoline moiety of a (benzo[b]thiophen-2-yl)quinoline cyclometalated ligand along with ancillary picolinate. The fundamentals of the origin of AIPE on Ir2 and Ir4 and its associated excited-state properties are deeply studied through comparison with unsubstituted Ir1 with the help of density functional theory and single-crystal X-ray diffraction analysis. Most importantly, AIPE-active Ir2 is employed for the development of efficient deep-red and NIR PhOLEDs by hybrid solution-processable methods, in which the AIPE effect of Ir2 reaches a maximum external quantum efficiency (EQE) of 7.29% at high doping ratios.
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Electroplex emission is rarely seen in ruthenium polypyridyl complexes, and there have been no reports from light-emitting electrochemical cells (LECs) to date. Here, for the first time, near-infrared (NIR) emission via the electroplex mechanism in a LEC based on a new blend of ruthenium polypyridyl complexes is described. The key factor in the design of the new complexes is the 0.4 V decrease in the oxidation half-potential of Ru(II)/Ru(III) in [Ru(DPCO)(bpy)2]ClO4 (DPCO = diphenylcarbazone, bpy = 2,2 bipyridine), which is about one-third of the value for benchmark [Ru(bpy)3](ClO4)2, as well as the long lifetime of excited states of 350–450 ns. The LEC based on the new blend with a narrow band gap (≈1.0 eV) of a Ru(DPCO) complex and Ru(bpy)3²⁺ can produce an electroluminescence spectrum centred at about 700 nm, which extends to the NIR region with a high external quantum efficiency (EQE) of 0.93% at a very low turn-on voltage of 2.6 V. In particular, the very simple LEC structure was constructed from indium tin oxide (anode)/Ru(DPCO):Ru(bpy)3²⁺/Ga:In (cathode), avoiding any polymer or transporting materials, as well as replacing Al or Au by a molten alloy cathode. This system has promising applications in the production of LECs via microcontact or inkjet printing.
Article
Purpose Stability of dental implants is an important factor for evaluation of osseointegration. The aim of this study was to evaluate the effect of combined use of low-level laser (LLL) and light-emitting diode (LED) therapy on the stability of dental implants during the healing phase. Materials and Methods This was a randomized clinical trial. Patients were assigned to two groups: In group 1, patients received LLL and LED 20 min/day for 10 days after implant insertion. Patients in group 2 (controls) did not undergo LLL and LED. The implant stability quotient (ISQ) was measured at 0 (time 0), 10 (time 1), 21 (time 2), 42 (time 3) and 63 days (time 4) after implant placement. Independent t test was used to compare the ISQs between the two groups. Results Fifty-eight patients were studied in two groups (n = 28). The mean ISQ did not differ immediately after insertion (P > 0.05). The mean ISQ differed significantly between the two groups on days 10, 21, 42 and 63 (P < 0.05). Results demonstrated an increase in the amount of ISQ in group 1 (intervention) at times 1, 2, 3 and 4. In the control group, the amount of ISQ decreased on days 10 and 21 following implant insertion, but increased afterward on days 42 and 63. Conclusion The results of this study showed that simultaneous use of LLL and LED increased the stability of the implants after 9 weeks of follow-up.
Article
This paper reports nerve growth factor functionalized superparamagnetic iron oxide-gold core-shell nanoparticles (NGF-SPIO-Au NPs), an engineered nanomedicine for non-invasive neuron regeneration when irradiated by a low-intensity light-emitting diode (LED). NGF-SPIO-Au NPs of 20 μg/ml, were tested on PC-12 neuron-like cells, irradiated by LEDs (525 nm, 1.09, 1.44, and 1.90 mW/cm2). A remarkable Ca2+ influx was detected in differentiated PC-12 cells treated with NPs, irradiated by LED of 1.90 and 1.44 mW/cm2 with great cell viability (>84%) and proliferations. The strong heat generated through their plasmonic surface upon LED irradiation on NGF-SPIO-Au NPs was observed. For cells treated with LED (1.90 mW/cm2) and NGF-SPIO-Au NPs, a dramatic enhancement of neuronal differentiation (83%) and neurite outgrowth (51%) was found, and the upregulation of both the neural differentiation specific marker (β3-tubulin) and the cell adhesive molecule (integrin β1) was observed by the reverse transcription-polymerase chain reaction and western blot analysis.
Article
The aim of this study was to evaluate the effectiveness of pain modulation following Laser or LED phototherapies during the process of tooth separation. This was a longitudinal randomized controlled clinical trial in four observational times carried out in 60 patients (15 males, 45 females, average 24.1 years old) who were randomly divided into three groups: G1 (LED, AsGaAl, λ850 ± 10 nm, 150 mW, 17 J/cm², 57 s per session), G2 (Laser, AsGaAl, λ780 nm, 70 mW, 20.0 J/cm², 240 s per session) and G3 (Non-irradiated Control). All patients were submitted to tooth separation using elastomeric separators. The pain level was measured by using a visual analogue scale (VAS) immediately after insertion (T1) of the elastic, at 48 (T2), 96 (T3) hours and 6 days (T4). It was observed an increase of the pain on the Control group from T1 to T2, with statistical significance. Pain levels in the LED and Laser groups were always significantly lower (<0.001), except for T1. According with the results of the present study it may be concluded that, either LED or Laser phototherapies, were effective in reducing the pain level after dental separation process when compared to the control group.
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As NASA prepares for longer space missions aiming for the Moon and Mars, astronauts' health and performance are becoming a central concern due to the threats associated with galactic cosmic radiation, unnatural gravity fields, and life in extreme environments. In space, the human brain undergoes functional and structural changes related to fluid shift and intracranial pressure. Behavioral abnormalities, such as cognitive deficits, sleep disruption, and visuomotor difficulties, as well as psychological effects, are also a concern. We discuss opportunities and challenges of noninvasive brain stimulation (NiBS) methods - including transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES) - to support space exploration in several ways. NiBS includes safe and portable techniques already applied in a wide range of cognitive and motor domains, as well as therapeutically. NiBS could be used to enhance in-flight performance, supporting astronauts during pre-flight Earth-based training, as well as to identify biomarkers of post-flight brain changes for optimization of rehabilitation/compensatory strategies. We review these NiBS techniques and their effects on brain physiology, psychology, and cognition.
Chapter
Chronic wounds are characterized by a failure to re-epithelialize and by defective production as well as remodeling of extracellular matrix (ECM). Acute incisional and excisional skin wounds account for over 4.5 million medical procedures per year in the US. Therapies that accelerate normal skin repair and production of stronger scar tissue are desirable, because they lead to quicker recovery from burns and surgical operations, particularly in older individuals. Therapies that heal chronic wounds save tissue that might otherwise be lost to necrosis and infection as well as save the life of the patient in some cases. Deep incisions are repaired by stitching the wound edges together, resulting in a thin line of scar tissue on the surface of the skin. To increase the area that can be covered by a skin autograft, surgeons use meshed split-thickness skin grafts (MSTSGs). A wide variety of topical agents have been employed to accelerate the normal repair process and produce stronger scar tissue in acute wounds of normal skin. Application of healing accelerants as early as possible after wounding is desirable, because of the cascade affects that carry through to later stages of healing. No dental restorative materials have the same physical and chemical characteristics of natural tooth tissues. The current technique to restore periodontal tissue is guided by tissue regeneration, which does not produce predictably good outcomes. Cornea is unable to regenerate if limbal tissue that provides the stem cells for regeneration is compromised. If a part of the limbus in either eye remains undamaged, pieces of this tissue can be removed and cultured on human amniotic membrane to form a larger sheet. Pieces of this epithelial sheet can then be transplanted as an autogeneic sectorial or a ring graft to regenerate and maintain the damaged cornea.
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To explore the safety and feasibility of low fluence intense pulsed light (IPL) for treating pediatric patients with moderate-to-severe blepharitis and to analyze potential factors associated with the recovery of meibomian glands (MG) dropout, a retrospective, noncomparative study, including 17 blepharitis patients (33 eyes) aged between 5 and 16 years old was conducted. All of the participants were given 4 continuous sessions of low-fluence (9–12 J/cm2) IPL at 3–4 week intervals. Corneal fluorescein staining (CFS), tear breakup time (BUT), inferior tear meniscus height, Demodex presence, and MG morphology were examined before and after the treatment. Results indicated that CFS, BUT and MG morphology (central/total gland area ratio and gland signal index) had significantly improved (p < 0.05). Symptoms and signs such as severe corneal neovascularization, limbal pannus and conjunctival congestion also subsided. Among age, gender, presence of Demodex and interval before diagnosis, age initiating the formal treatment was confirmed as a negatively correlated factor of the recovery of MG dropout (p = 0.032, B = −1.755). No notable adverse events were reported. In conclusion, low fluence IPL seems to be a safe and effective alternative for moderate-to-severe pediatric blepharitis, and MG dropout is prone to recover in younger patients.
Article
Probiotics are nonpathogenic bacterial strains that exert beneficial effects on the host. Previous studies have shown that topical use of some strains of probiotic bacteria have good effects on the healing of cutaneous wounds. In the current study, the wound healing potentials of bacterial probiotics on diabetic cutaneous wounds were evaluated. The effects of probiotics on migration, the viability of fibroblasts, and macrophage proliferation were measured through using wound healing assay, methylthiazol tetrazolium assay, and bromodeoxyuridine, respectively. In this regard, in vivo diabetic wound healing experiments in Wistar rats following treatment with nontoxic concentrations of Lactobacillus bulgaricus and Lactobacillus plantarum were conducted. The histopathological and gene expression analyses were performed following removal of wound sites 3, 7, and 14 days postwounding. Results showed that treatment with probiotics accelerated the healing process of diabetic wounds and modulated the inflammatory cells in wound sites during a 14‐day period postwounding. The altered mRNA levels of inflammatory cytokines were observed in wound sites following treatment with probiotics. The findings of the current study reveal that L. bulgaricus and L. plantarum could improve the healing of diabetic wounds via regulation of inflammation. Treatment with L. bulgaricus and L. plantarum accelerated the wound healing process in the diabetic Wistar rats.
Article
Background Low level light therapy is a recent aaddition to the pantheon of light-based therapeutic interventions. Termed “photobiomodulation”, the absorption of red/near infrared light energy induces enhancement of mitochondrial ATP production, cell signaling and growth factor synthesis and attenuates oxidative stress. Photobiomodulation is highly commercialized with devices marketed directly to the consumer. In the grey area between the commercial and therapeutic sectors, harnessing the clinical potential in reproducible and scientifically measurable ways remains challenging. Objectives This article presents a summary of the clinical evidence for photobiomodulation and discusses the regulatory framework for low level light therapy Methods A review of the clinical literature pertaining to the use of low level light therapy for skin rejuvenation (facial rhytids and dyschromias), acne vulgaris, wound healing, body contouring and androgenic alopecia was performed. Results A reasonable body of clinical trial evidence exists in support of the role of low energy red/near infrared light as a safe and effective method of skin rejuvenation, treatment of acne vulgaris, alopecia and, especially, body contouring. Methodological flaws, small patient cohorts and industry funding mean there is ample scope to improve the quality of evidence. It remains unclear if LED-based light sources induces physiologic effects of the nature and magnitude of laser-based systems which were used in most of the higher quality studies. Conclusions Low level light therapy is here to stay. However, its ubiquity and commercial success has outpaced the empirical approach on which solid clinical evidence is established. Thus, the challenge is to prove its therapeutic utility in retrospect. Well-designed, adequately powered, independent clinical trials will help us answer some of the unresolved questions and enable the potential of this therapy to be realized.
Article
Photo-biomodulation (PBM) also known as low-level laser therapy is a rising technology with multiple potential uses in medicine and recently in the cosmetic field for the treatment of skin conditions and skin rejuvenation. Due to its wound healing and anti-inflammatory properties, there is an increase in popularity in its use as adjunctive treatment before and after surgical procedures in the face and neck.
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Photobiomodulation (PBM) has evolved as a rapidly growing therapeutic biophysical non-invasive approach for the acceleration of tissue repair, mitigation of pain, inflammation and restoration of cellular functions. This study compares the PBM effect of pulsed-mode (10 Hz) of NIR laser (810 nm) and LED (808 ± 3 nm) with identical treatment regimen (average power 70 mW; average irradiance 40 mW/cm²; total fluence 24 J/cm², duty cycle 50%; pulse duration 50 msec; peak irradiance 80 mW/cm²; 10 min exposure once daily for 7 days) on full-thickness, third-degree burn wound in rat using comprehensive analysis of quantitative label-free global proteomics, followed by validation of the proteomics data by various biophysical, biochemical, molecular, histological and immunohistochemical (IHC) assays. The proteomic analysis clearly revealed the common biological processes indicated by modulation of similar biological pathways (known for tissue repair process) associated with neuronal (4), metabolic (10), vascular (3), inflammation (4) and cell signaling (12) in both laser and LED treated groups. Validation of proteomic analysis using various healing markers demonstrated attenuated inflammatory response like decreased TNF-α, IL-1β, IL-6, COX-2 levels (ELISA), enhanced cellular proliferation (PCNA, TGF-β2), collagen, ECM accumulation (biochemical, H&E, Masson's trichrome staining, IHC assays), wound contraction and cytoprotection (TUNEL assay) in both laser and LED-treated groups as compared to the control. Collectively, the proteomics data revealed previously know molecules along with novel identified molecules post-PBM treatment, which broaden the understanding of tissue repair mechanisms. This study profoundly signifies that both laser and LED in 810 nm wavelength range at pulsed-mode (10 Hz) are equally effective for PBM-mediated potential treatment to accelerate burn wound healing.
Article
Background The aim of this study was to investigate the influence of three different light-emitting diode (LED) wavelengths on the proliferation and osteoblastic differentiation of periodontal ligament stem cells (PDLSCs) in vitro. Methods PDLSCs seeded on 96- and 24-well plates, for proliferation and osteoblastic differentiation, respectively, were irradiated daily by LED light with peak emission wavelengths of 630, 680, and 830 nm at constant energy densities of 3.5 J/cm². Cultures were grown for 8 days for the proliferation assay, 10 days for the alkaline phosphatase (ALP) assay, and 28 days for Alizarin red staining. Mitochondrial activity, ALP enzyme level, and the ability to form calcium phosphate deposits were measured and compared across cultures. Results Results obtained from statistical analysis of the experimental data indicated that the rate of proliferation (P < 0.05) in 830-nm irradiated cultures were significantly higher than the control samples at day 6 and 8; whereas, for the 630- and 680-nm groups, test results showed lower proliferation rates at day 8. For osteoblastic differentiation, significantly greater mineralization than the control samples was detected in the red-light groups (630 and 680 nm) during the late differentiation period (P < 0.001), which was supported by a higher ALP activity of the 630- and 680-nm groups in the early stage (P < 0.01). Conclusion The results of this study demonstrate that the PDLSCs responded differently to specific LED wavelengths. For enhancing cellular proliferation, 830-nm LED irradiation was more effective. On the other hand, the wavelengths of 630 and 680 nm were better for stimulating osteoblastic differentiation.
Article
Aim. To substantiate the application of the infrared range narrow-band optical radiation and kinesiotaping combined effect in the complex treatment of patients with posterior cervical sympathetic syndrome on the basis of clinical studies. Material and methods. The dynamics of complaints for dizziness in 60 patients of two groups were evaluated using the DHI (Dizziness Handicap Inventory) and VRBQ (Vestibular Rehabilitation Benefit Questionnaire) scales, headache and pain in the neck using the visual analog scale (VAS), tinnitus, visual defocusing, nausea, vomiting, palpitations, decreased concentration and attention using the International Classification of Functioning, Disability and Health (ICF). To assess the posture, the shoulder Aksenova index was used. A duplex scan of the brachycephalic arteries and an assessment of anxiety and depression on the Sheehan and Beck scales, respectively, were used to assess blood flow through the vertebral arteries. Results. Statistically reliable data (p <0.05) for reducing dizziness, headache, pain in the cervical region, reducing the severity of tinnitus, defocusing vision, nausea, and decreasing concentration and attention were obtained in the group using the combined effects of narrow-band infrared optical radiation and kinesiotherapy in comparison with the control group. Statistically reliable data (p <0.05) for improving linear velocity of blood flow Vm, Vps for the left vertebral artery at the extracranial level and statistically reliable data (p<0.05) for improving linear velocity of blood flow Vm, Vps for vertebral arteries were obtained at the intracranial level. Statistically reliable data (p<0.05) on the effectiveness of kinesiotaping for the correction of the upper cross syndrome were obtained. Conclusion. The application of the narrow-band infrared range optical radiation and kinesioteping combined exposure can be recommended in the complex treatment of patients with posterior cervical sympathetic syndrome as well as to increase the linear velocity of blood flow in the vertebral arteries, the use of kinesiotaping can be recommended for the correction of biomechanical disorders, correction of the upper cross syndrome.
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Recently, Far-infrared Light Emitting Diodes have attracted considerable interest in the research field worldwide. Emerging light therapy requires effective red/far-infrared light resources in clinical and plant photomorphogenesis to target or promote the interaction of light with living organisms. Here, Gd 3 Al 4 GaO 12 :Cr ³⁺ (hereinafter referred to as: GAGG:Cr ³⁺ ) phosphor was synthesized by high-temperature solid-phase method, and the crystal structure, morphology, and luminescence properties of this series of phosphor samples were studied. Through X-ray powder diffraction to obtain pure phase GAGG:Cr ³⁺ series phosphor. Under the excitation of 420nm blue light, a broad band emission from 640 to 850nm is obtained, which is the result of the transition of Cr ³⁺ ⁴ T 2 → ⁴ A 2 level. A sharp emission peak at 693nm is the R line belonging to Cr ³⁺ in Gd 3 Al 4 GaO 12 garnet. R line is assigned to the spin-forbidden ² E→ ⁴ A 2 transitions of Cr ³⁺ ions that occupy the ideal octahedral sites. As the Cr ³⁺ doping concentration increases, the luminous intensity of the sample increases first and then decreases. When the doping concentration of Cr ³⁺ is 0.1mol phosphor,the luminous intensity is strongest at one single broad peak at about 712nm. At 440k, the R sharp line (693nm) and broad band (712nm) emission intensity maintained 78.6% and 71.8% , compared to room temperature intensity, respectively. The change of fluorescence lifetime at different temperatures gives the mechanism of fluorescence change with temperature. The current exploration will pave a promising way to engineer GAGG:Cr ³⁺ activated optoelectronic devices for all kinds of photobiological applications.
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Staphylococcus aureus is a serious threat to public health due to the rise of antibiotic resistance in this organism, which can prolong or exacerbate skin and soft tissue infections (SSTIs). Methicillin-resistant S. aureus is a Gram-positive bacterium and a leading cause of SSTIs. As such, many efforts are underway to develop therapies that target essential biological processes in S. aureus . Antimicrobial photodynamic therapy is effective alternative to antibiotics, therefore we developed an approach to simultaneously expose S. aureus to intracellular and extracellular photoactivators. A near infrared photosensitizer was conjugated to human monoclonal antibodies (mAbs) that target the S. aureus Isd heme acquisition proteins. Additionally, the compound VU0038882 was developed to increase photoactivatable porphyrins within the cell. Combinatorial PDT treatment of drug-resistant S. aureus exposed to VU0038882 and conjugated anti-Isd mAbs proved to be an effective antibacterial strategy in vitro and in a murine model of SSTIs.
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Purpose: To investigate the efficacy of intense pulsed light (IPL) treatment in patients with meibomian gland dysfunction (MGD) associated with Sjögren’s syndrome.Methods: This study included 43 patients with MGD and Sjögren’s syndrome. Patients received either IPL with meibomian gland expression (IPL/MGX) (n = 22) or MGX only (n = 21). Treatments were administered three times at a 3-week interval. Patients were followed up 6 weeks after the end of the treatment. Ocular Surface Disease Index (OSDI), tear film breakup time with fluorescein dye (FBUT), non-invasive tear breakup time, tear meniscus height (TMH), Schirmer test, SICCA ocular surface staining score, meibum quality score (MQS), and meibum expression score (MES) were evaluated at each visit. Meibomian gland dropouts (meiboscore) and tear film lipid layer grade were measured using keratography.Results: OSDI, FBUT, corneal surface staining score, MQS, meiboscore, and tear film lipid layer grade improved after IPL/MGX treatment (p < 0.05). In both treatment groups, MES significantly improved (p < 0.01 and p < 0.05 for IPL/MGX and MGX groups, respectively). The Schirmer test score, conjunctival surface staining score, and TMH after treatment were not significantly different between the groups. After treatment, the IPL/MGX group had significantly lower OSDI, FBUT, corneal staining score, MQS, and MES, but higher FBUT, compared with the MGX group (p < 0.05).Conclusions: IPL treatment effectively improved tear film, ocular surface parameters, meibomian gland function, and lipid layer grade in patients with Sjögren’s syndrome and MGD.
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Introduction Liposuction has undergone many revisions since 1980, the most notable being the introduction of the tumescent technique of local anesthesia by Jeffery Klein, MD. Since then, in an effort to improve the aesthetics of the technique and the ease and safety of the procedure, other techniques have been introduced. These include superficial liposuction, UAL, external ultrasonic liposuction, mechanically assisted liposuction, and, most recently, laser-assisted liposuction. Materials and Methods Four centers in the United States, operating under an 1RB protocol, performed liposuction with the tumescent technique of local anesthesia on specified cosmetic units of the body. One side was exposed to 635-nm laser therapy after tumescence was achieved, whereas the contralateral side was not. Observations were recorded during surgery and at 2 weeks postoperatively. Results Observations of intraoperative technique did not show an advantage to laser-assisted liposuction. Observations of the postoperative course were equivocal, though there was evidence of reduction of edema in certain patients. Discussion The addition of laser therapy to liposuction technique is based on years of experience demonstrating improved wound healing using a technique of low-level laser therapy. Although the recorded observations did not support an advantage to the addition of laser therapy, there was a paradoxical difference of opinion among patients and surgeons who participated in the study. These individuals believed that, compared with patients not treated with low-level laser therapy, there was at least a reduction in degree and duration of postoperative pain and induration. As low-level laser therapy may have systemic effects on wound healing, comparing treated and untreated contralateral sides may not be valid because both sides experienced improvements in postoperative course. Laser-assisted liposuction has a potential advantage, not supported by this study, in the intraoperative and postoperative course of liposuction surgery. New studies using double-blind techniques will need to be conducted.
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This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program. Studies on cells exposed to microgravity and hypergravity indicate that human cells need gravity to stimulate cell growth. As the gravitational force increases or decreases, the cell function responds in a linear fashion. This poses significant health risks for astronauts in long termspace flight. LED-technology developed for NASA plant growth experiments in space shows promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. This LED-technology is also biologically optimal for photodynamic therapy of cancer. .
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Different types of osteoblast behavior result from external stimulation in the early and in the late stages of cell differentiation. The purpose of this study was to investigate the influence of a diode laser on osteoblasts and to compare any effects between the proliferating and the differentiating phases. In the proliferating phases, the numbers of cells greatly increased in the laser irradiated group as compared with that of the control group. The increases in the numbers of cells in the differentiating phase were no greater than were those in the proliferating phase. The alkaline phosphatase activity of cells in the proliferating phase was highest 5 days after the laser irradiation, however, the activity in the differentiating phase increased day by day. Although osteopontin mRNA levels in the proliferating phase increased in the first 3 days of culture and then decreased in both groups, this decrease of osteopontin mRNA was small in the irradiated group. In contrast, osteopontin mRNA expression in the differentiating phase increased at day 1 and then decreased in the control group, while osteopontin mRNA levels in the irradiated group did not decrease.
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Space light-emitting diode (LED) technology has provided medicine with a new tool capable of delivering light deep into tissues of the body, at wavelengths which are biologically optimal for cancer treatment and wound healing. This LED technology has already flown on Space Shuttle missions, and shows promise for wound healing applications of benefit to Space Station astronauts.
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The acceleration of bone regeneration by low-intensity laser irradiation may hold potential benefits in clinical therapy in orthopedics and dentistry. The purpose of this study is to compare the effects of light-emitting diode (LED) and laser on pre-osteoblast MC3T3 proliferation and differentiation. Cells were irradiated with red, infrared, and LED (3 and 5 J/cm(2)). Lasers had a power density of 1 W/cm(2) and irradiation time of 2 and 5 s. LED had a power density of 60 mW/cm(2) and irradiation time of 50 and 83 s. Control group did not receive irradiation. Cell growth was assessed by a colorimetric test (MTT) (24, 48, 72, and 96 h), and cell differentiation was evaluated by alkaline phosphatase (ALP) quantification after growth in osteogenic medium (72 and 96 h and 7 and 14 days). At 24 h, the cell growth was enhanced 3.6 times by LED (5 J/cm(2)), 6.8 times by red laser (3 J/cm(2)), and 10.1 times by red laser (5 J/cm(2)) in relation to control group (p < 0.05). At the other periods, there was no influence of irradiation on cell growth (p > 0.05). The production of ALP was not influenced by irradiation at any period of time (p > 0.05). Low-intensity laser and LED have similar effects on stimulation of cell growth, but no effect on cell differentiation.
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Iron deficiency impairs the formation of hemoglobin, red blood cells, as well the transport of oxygen. The wound healing process involves numerous functions, many of which are dependent on the presence of oxygen. Laser has been shown to improve angiogenesis, increases blood supply, cell proliferation and function. We aimed to study the effect of λ660 nm laser and λ700 nm light-emitting diode (LED) on fibroblastic proliferation on cutaneous wounds on iron-deficient rodents. Induction of iron anemia was carried out by feeding 105 newborn rats with a special iron-free diet. A 1 × 1 cm wound was created on the dorsum of each animal that were randomly distributed into seven groups: I, control anemic; II, anemic no treatment; III, anemic + L; IV, anemic + LED; V, healthy no treatment; VI, healthy + laser; VII, healthy + LED (n = 15 each). Phototherapy was carried out using either a diode laser (λ660 nm, 40 mW, 10 J/cm(2)) or a prototype LED device (λ700 ± 20 nm, 15 mW, 10 J/cm(2)). Treatment started immediately after surgery and was repeated at 48-h interval during 7, 14, and 21 days. After animal death, specimens were taken, routinely processed, cut, stained with hematoxylin-eosin, and underwent histological analysis and fibroblast counting. Significant difference between healthy and anemic subjects on regards the number of fibroblast between treatments was seen (p < 0.008, p < 0.001). On healthy animals, significant higher count was seen when laser was used (p < 0.008). Anemic subjects irradiated with LED showed significantly higher count (p < 0.001). It is concluded that the use of LED light caused a significant positive biomodulation of fibroblastic proliferation on anemic animals and laser was more effective on increasing proliferation on non-anemics.
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The purpose of this was to evaluate the neuroprotective effects of near-infrared (NIR) light using an in-vivo rodent model of traumatic brain injury (TBI), controlled cortical impact (CCI), and to characterize changes at the behavioral and biochemical levels. NIR upregulates mitochondrial function, and decreases oxidative stress. Mitochondrial oxidative stress and apoptosis are important in TBI. NIR enhanced cell viability and mitochondrial function in previous in-vitro TBI models, supporting potential NIR in-vivo benefits. Sprague-Dawley rats were divided into three groups: severe TBI, sham surgery, and anesthetization only (behavioral response only). Cohorts in each group were administered either no NIR or NIR. They received two 670 nm LED treatments (5 min, 50 mW/cm(2), 15 J/cm(2)) per day for 72 h (chemical analysis) or 10 days (behavioral). During the recovery period, animals were tested for locomotor and behavioral activities using a TruScan device. Frozen brain tissue was obtained at 72 h and evaluated for apoptotic markers and reduced glutathione (GSH) levels. Significant differences were seen in the TBI plus and minus NIR (TBI+/-) and sham plus and minus NIR (S+/-) comparisons for some of the TruScan nose poke parameters. A statistically significant decrease was found in the Bax pro-apoptotic marker attributable to NIR exposure, along with lesser increases in Bcl-2 anti-apoptotic marker and GSH levels. These results show statistically significant, preclinical outcomes that support the use of NIR treatment after TBI in effecting changes at the behavioral, cellular, and chemical levels.
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The aim of this study was to examine the reactive oxygen species (ROS) that are dissipated by 635 nm irradiation, and the effect of 635 nm irradiation on ROS scavenging system. Intracellular ROS are produced in the form of superoxide anion by either nicotinamide adenine dinucleotide phosphate (NADPH) oxidase or xanthine oxidase in response to a number of stimuli. Low-level light irradiation decreases the intracellular ROS level and has been used in clinical situations for reducing the level of oxidative stress. Human epithelial cells were exposed to exogenous and endogenous oxidizing agents that promote the generation of harmful ROS. These were then irradiated with 635 nm LED light, 5 mW/cm(2) for 1 h, 18 J/cm(2) or by 470 nm LED light, also 5 mW/cm(2) for 1 h, 18 J/cm(2) on a 9 cm cell culture dish. After irradiation, the MTT reduction method and malondialdehyde (MDA) colorimetric assay were performed in xanthine/xanthine oxidase (XXO)- or hydrogen peroxide (H(2)O(2))-treated HaCaT cells. The superoxide anion was detected by an electron spin resonance (ESR) spectrometer using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin trap and H(2)O(2) was assayed by flow cytometry using 2',7'-dichlorodihydrofluorescein diacetate (H(2)DCF-DA). Irradiation at 635 nm enhanced cell viability in the XXO-treated HaCaT cells. Also, irradiation had a much lesser effect on cell viability in the HaCaT cells treated with exogenous H(2)O(2) as compared with that in cells treated with N-acetyl-L-cysteine. The level of the superoxide anion increased in response to XXO treatment, and then decreased after 635 nm irradiation. Irradiation with 635 nm led to a decrease in superoxide anion and lipid peroxidation levels in the presence or absence of diethyldithiocarbamate. These results highlight the potential role of 635 nm irradiation in protection against oxidative stress by scavenging superoxide anions. Also, a pathway that is independent of the activities of intracellular enzymatic ROS scavengers, such as superoxide dismutase, glutathione peroxidase and catalase might be involved in its mechanism of action.
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Background and Objective Low-level laser irradiation at certain fluences and wavelengths can enhance the release of growth factors from fibroblasts and stimulate cell proliferation in vitro. We evaluated whether low-level laser irradiation can improve wound healing in diabetes mellitus.Study Design/Materials and Methods Genetically diabetic mice (C57BL/Ksj/db/db) were used as the animal model for this wound healing study. The experimental animals were divided among four groups: negative control, positive control (topical basic fibroblast growth factor [bFGF] on wound), laser therapy group; and a combination group of laser therapy and topical bFGF. An argon dye laser (Lexel Auora Model 600) at a wavelength of 630 nm and an output of 20 mW/cm2 was used as the light source. The speed of wound closure and histological evaluation were used to analyze the experimental results.ResultsLaser irradiation enhanced the percentage of wound closure over time as compared to the negative control group (58.4 ± 2.6 vs. 40.8 ± 3.4 at day 10 and 95.7 ± 2 vs. 82.3 ± 3.6 at day 20, P < .01). Histological evaluation showed that laser irradiation improved wound epithelialization, cellular content, granulation tissue formation, and collagen deposition in laser-treated wounds as compared to the negative control group (6.4 ± 0.16 vs. 3.8 ± 0.13 at day 10 and 12 ± 0.21 vs. 8.2 ± 0.31, P < .01).Conclusion This study of laser biostimulation on wound healing in diabetic mice suggests that such therapy may be of great benefit in the treatment of chronic wounds that occur as a complication of diabetes mellitus. Lasers Surg Med 20:56–63, 1997. © 1997 Wiley-Liss, Inc.
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The aim of this study was to compare the effects of Low-intensity Laser Therapy (LILT) and Light Emitting Diode Therapy (LEDT) of low intensity on the treatment of lesioned Achilles tendon of rats. The experimental model consisted of a partial mechanical lesion on the right Achilles tendon deep portion of 90 rats. One hour after the lesion, the injured animals received applications of laser/LED (685, 830/630, 880 nm), and the same procedure was repeated at 24-h intervals, for 10 days. The healing process and deposition of collagen were evaluated based on a polarization microscopy analysis of the alignment and organization of collagen bundles, through the birefringence (optical retardation-OR). The results showed a real efficiency of treatments based on LEDT and confirmed that LILT seems to be effective on healing process. Although absence of coherence of LED light, tendon healing treatment with this feature was satisfactory and can certainly replace treatments based on laser light applications. Applications of infrared laser at 830 nm and LED 880 nm were more efficient when the aim is a good organization, aggregation, and alignment of the collagen bundles on tendon healing. However, more research is needed for a safety and more efficient determination of a protocol with LED.
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The purpose of this study was to evaluate the clinical effectiveness of a LED phototherapy prototype apparatus in the healing of nipple trauma in breastfeeding women. There is no scientific evidence of an effective treatment for nipple trauma. The experimental group was treated with orientation on nipple care and adequate breastfeeding techniques in addition to active LED phototherapy. The control group was treated with orientation on nipple care and adequate breastfeeding techniques in addition to placebo LED phototherapy. Participants were treated twice a week, for a total of eight sessions. Healing of the nipple lesions was measured by a reduction in their area, and decrease in pain intensity was measured in accordance with an 11-point Pain Intensity Numerical Rating Scale and a standard 7-point patient global impression of change. Statistically significant reductions in measured nipple lesion area (p<0.001) were observed for both the experimental and control groups with an increase in the number of treatment sessions. A significant difference between the experimental and control groups was observed for the healing of nipple lesions (p<0.001). The pain intensity was significantly reduced only in the experimental group (p<0.001). Preliminary results demonstrated the prototype apparatus for LED phototherapy to be an effective tool in accelerating the healing of nipple trauma.
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This work carried out a histological analysis on bone defects grafted (MTA) treated or not with LED, BMPs, and membrane (GBR). Benefits of their isolated or combined usage on bone repair were reported, but not their association. Ninety rats were divided into ten groups and each subdivided into three. Defects on G II and I were filled with the blood clot. G II was further LED irradiated. G III and IV were filled with MTA; G IV was further LED irradiated. In G V and VI, the defects were filled with MTA and covered with a membrane (GBR). G VI was further LED irradiated. In G VII and VIII, BMPs were added to the MTA and group VIII was further LED irradiated. In G IX and X, the MTA + BMP graft was covered with a membrane (GBR). G X was further LED irradiated. LED was applied over the defect at 48-h intervals and repeated for 15 days. Specimens were processed, cut, and stained with H&E and Sirius red and underwent histological analysis. The use of LED light alone dramatically reduced inflammation. However, its use on MTA associated with BMP and/or GBR increased the severity of the inflammatory reaction. Regarding bone reabsorption, the poorest result was seen when the LED light was associated with the MTA + BMP graft. In the groups Clot and MTA + GBR, no bone reabsorption was detectable. Increased collagen deposition was observed when the LED light was associated with the use of the MTA associated with BMP and/or GBR. Increased new bone formation was observed when the LED light was used alone or associated with the use of MTA + GBR, MTA + BMP, on association of MTA + BMP + GBR and when BMP was added to the MTA. Our results indicate that the use of LED light alone or in association with MTA, MTA + BMP, MTA + GBR, and MTA + BMP + GBR caused less inflammation, and an increase of both collagen deposition and bone deposition as seen on both histological and morphometric analysis.
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An alternative approach in the treatment of acne vulgaris is photodynamic therapy (PDT) that uses light and aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) production to eradicate Propionibacterium acnes found in acne lesions. PpIX formation is dependent on ALA percutaneaous penetration. In this study, to enhance ALA penetration and subsequent accumulation of PpIX, skin temperature was increased with radiant infrared (IR) prior to ALA-PDT application and compared to ALA-PDT alone in the treatment of inflammatory acne. Ten patients exhibiting inflammatory acne with a lesion count of > or =10 were assigned to a split face or split back group. One side was pre-treated for 15 minutes with radiant IR light emitting diode (LED) (970 nm), while the other side was used as control. ALA was then applied after which PDT LED (630 nm) was performed on the entire face or back surface. Blinded lesion counts and clinical global assessment of severity were performed based on digital photographs before and 4 weeks after the PDT procedure. This randomized, controlled, and rater-blinded trial revealed a significant difference in median reduction of inflammatory lesions on the IR pre-treated (73%, 95% confidence interval (CI) 51-81%) versus the control side (38%, 95% CI 8-55%) 1 month after PDT (P<0.0001). Clinical assessment of severity was also significantly lower on the IR-treated side than on the control side (median 1, 95% CI 0.74-1.34 vs. 2, 95% CI 1.17-1.72). No unusual treatment-related adverse effects were observed. The reported therapeutic effects may be due to enhanced induction of alterations in transcutaneous diffusion kinetics of the photosensitizer at higher skin temperature and/or conversion of ALA to PpIX. Pre-PDT radiant IR LED exposure appears to be a promising method to enhance PDT efficacy for the treatment of acne lesions.
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This paper reviews studies on the basic principles of biostimulation of wound healing by various low-energy lasers. It looks at the mechanism of action of biostimulation as well as the lasers effect on cell proliferation, collagen synthesis, and would healing.
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Aim of the study was to compare different wavelength laser immunological reactions.
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The mechanism of wound healing was studied with 35S, 14C labelled amino acids during the early proliferative phase, following artificial incision. The measurements show that 4 joule laser energy applied at the earliest time favourably influences wound healing; the production of collagen in the cicatricial tissue treated with laser exceeds that of the control by about 30-50 per cent.
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Introduction: Light-emitting diode (LED) therapy uses different wavelengths of light and has been reported to accelerate cutaneous wound healing. Carnosic acid is an antioxidant that is also thought to be photoprotective. We designed an in vitro study to examine the effects of LED and carnosic acid on the proliferation and migration of human keratinocytes. Materials and Methods: Clinically normal human keratinocytes were cultured and exposed to two wavelengths: 620 nm and 660 nm LED at different ß uences. In the second part of this study, a different batch of human keratinocytes was grown in culture, and different concentrations of carnosic acid were added. Results: At the two wavelengths that were used, LED did not appear to have any therapeutic effect and was not effective in stimulating keratinocyte proliferation. Exposure to greater energy levels (increased fluence) produced increased cell damage that was directly proportional to the increase in energy. On the other hand, treatment of the cell cultures with the antioxidant carnosic acid resulted in an increase of keratinocyte cell proliferation, and this increase was also proportional to the concentration of carnosic acid. Conclusions: This study did not support the hypothesis that LED treatment results in keratinocyte proliferation; however, carnosic acid, a potent antioxidant, stimulated keratinocyte production and could be implicated in wound healing and rejuvenation.
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IntroductionLED light therapy with magnetostimulation (magnetoledtherapy) has a vast range of applications in the treatment of neurological, rheumatic and orthopedic illnesses. In some cases it serves as an alternative procedure to pharmacological treatment, in particular to nonsteroidal anti-inflammatory drugs.AimThe aim of this study was to discuss the use of magnetoledtherapy in the rehabilitation of children.Materials and methodsThis article is a review of selected literature and other available source materials.DiscussionDue to biological hysteresis, therapeutic outcomes of magnetoledtherapy appear later than in the case of other physical therapy methods; they last longer, even up to several months after the exposure, thus leading to more beneficial treatment effects. Therapeutic methods available for very young people are limited due to various contraindications. When exposure conditions are carefully considered and accounted for, magnetoledtherapy can be applied even in infants, serving as a beneficial complement to kinesiotherapy. Children willingly participate in such treatment because magnetoledtherapy produces few side effects and has a positive effect on a patient's well-being following the application. Selected indications for the use of this method in children include neuralgias, juvenile rheumatoid arthritis, collagenoses, aseptic necrosis, osteoporosis, tendinitis, tendovaginitis, bursitis, injuries without a disruption in tissue continuity including sprains, bruises and fractures, improvement in the quality and time of healing, burns, effects of exposure to sunlight and laser light, neonatal physiological jaundice, dermatoses including dermatitises, acne, herpes, vitiligo, psoriasis, central nervous system lesions, dental periapical lesions, cerebral palsy, peripheral nerve lesions, especially perinatal brachial plexus palsy, polyneuropathies, amyotrophic lateral sclerosis, spinal muscular atrophy, muscular dystrophies, congenital bone deformations, neuroses, sleep disorders, stress, Attention Deficit Hyperactivity Disorder (ADHD), speech impairment therapy and therapy for children with Down's syndrome. Therefore, this therapy is widely applicable. In the treatment of children, it is indispensible to strictly follow application parameters and observe specifications concerning the size of the area that is exposed to treatment.Conclusions Magnetoledtherapy is a valuable complement to the comprehensive rehabilitation of children and should be recommended for a wider application.
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A monolayer of HeLa cells in plateau-phase of growth was exposed to He-Ne laser radiation either 5 min, 60 min or 180 min before (gamma) -irradiation. It has been shown that in the case of a 5-min interval between the two types of irradiations the survival curve was practically identical to the survival curve of the cells after (gamma) -irradiation only. In the case of He-Ne laser exposure 60 min before (gamma) -irradiation with doses of over 5 Gy, a fraction of more resistant cells was revealed: their D0 was twice as high as the D0 of the min population. A preexposure of cells to He-Ne laser 60 or 180 min before (gamma) - irradiation also changed the shape of the growth curves as compared to (gamma) -irradiated cells. It is proposed that the preexposure of cells to He-Ne laser radiation activates, in a subpopulation of cells, processes which speed up the repair of (gamma) -radiation damage. The possibility that the described phenomenon is an adaptive response of cells is discussed.
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We report a 59-year-old Japanese male with diabetic ulcer successfully treated with xenon ray irradiation. The patient, having diabetes mellitus and heart disease, presented with a 1-month history of an unhealed cutaneous ulcer on his left foot. No treatment with topical application was effective. Therefore, xenon ray irradiation was administered. After irradiation was performed with a total dose of 142.7 J/cm2 over a treatment course of 10 weeks, the cutaneous ulcer improved. Xenon ray irradiation has a light source ranging from an ultra-violet wavelength to a near-infrared ray with a peak at 800-900 nm. Xenon ray treatment cutting off the ultra-violet wavelength has been introduced for the control of pain and the rehabilitation of patients with motor disturbances. Near-infrared irradiation is used to promote wound healing. This result indicates that xenon ray irradiation can be valuable for the treatment of cutaneous ulcer in patients with diabetes mellitus.
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This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program. LED-technology developed for NASA plant growth experiments in space shows promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. We present the results of LED-treatment of cells grown in culture and the effects of LEDs on patients’ chronic and acute wounds. LED-technology is also biologically optimal for photodynamic therapy of cancer and we discuss our successes using LEDs in conjunction with light-activated chemotherapeutic drugs.
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We have developed flexible ZnS:ErF3 alternating current thin film electroluminescent devices on molybdenum foils, and quantified the effect of insulator properties for the case of alumina (Al2O3) and barium tantalate (BaTa2O6) on the device electrical characteristics, and infrared emission. The inverted, full-stack structures could be flexed in tension and compression without mechanical failure or deterioration of optical output, and flex radii of a few centimeters are routinely achieved. Thus, the feasibility of a flexible, inorganic, large area electroluminescent emitter has been demonstrated. Compared to the Al2O3 devices, the numbers for structures employing BaTa2O6 represent a 29% increase in flux density at 980 nm, a 36% increase at 1540 nm, an 18% increase in conduction charge, a 10% increase in phosphor field and a 14% increase in threshold voltage. Our interpretation of the data is as follows: in the case of BaTa2O6, the interface states from which electrons are sourced into the phosphor are deeper, requiring a higher voltage for field emission. As a consequence, electrons are injected into the phosphor when the phosphor field is higher, resulting in better excitation efficiency and improved optical generation. The increase in conduction charge is interpreted as a higher density of interface states, which appear to have a narrower energy distribution based on the more abrupt threshold behavior observed.
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The purpose of this study was to evaluate the biological response and gene expression of New Zealand White Rabbit anterior cruciate ligament (ACL) fibroblasts for different wave lengths of light-emitting diode (LED) irradiation. In other words, this study was undertaken to evaluate the effects of different wavelengths of LED irradiation on cell growth, expression of extracellular matrix and growth factors, migration, and expression of actin and integrin. Proliferation assay showed that red (630 nm, 9.5 J/cm(2)) and green LED (530 nm, 9.8 J/cm(2)) irradiated cells were more increased than control group but there was no difference between the control group and the blue LED (460 nm, 27 J/cm(2)) irradiated group. Moreover, the expression of insulin-like growth factor, transforming growth factor-beta (TGF-β1), and collagen I were significantly increased in the red and green LED-irradiated group, but the expression of collagen was decreased in the blue LED-irradiated group. The results of staining showed that collagen and TGF-β1 were weaker in the control group and blue LED-irradiated cells, but stronger in the red and green LED-irradiated cells. Also, in the red and green LED-irradiated group, the expression of actin and integrin was not changed compared to the control group, but the expression of actin and integrin was decreased in the blue irradiated group. This study revealed that irradiation with a wavelength of 460 nm (blue LED) is cytotoxic to ACL cells, but irradiation with nontoxic fluencies of 530 (green LED) and 630 nm (red LED) wavelengths induced cell growth in cultured ACL cells.
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Background: The most common side effects of fractional carbon dioxide (CO2 ) laser resurfacing are erythema and edema of the treated skin. Light-emitting diode (LED) devices have been shown to stimulate fibroblast activity and hasten wound healing. The current study was designed to evaluate the efficacy of such LED devices in treating post-laser therapy erythema. Objectives: To evaluate the clinical efficacy of LED photomodulation in reducing erythema resulting from ablative fractional CO2 laser resurfacing. Materials and methods: Randomly selected facial halves of 10 Korean subjects (Fitzpatrick skin type III-IV) were treated using a 635-nm wavelength LED array immediately after full-face fractional laser skin resurfacing. Each participant was subsequently treated with LED daily for the following 7 days. Clinical photographs, subjective physician assessment, and chromometer erythema index were used to track the results, with clinical improvement assessed using a 5-point grading scale. Results: The postlaser erythema resolved faster on the experimental side than the control side, with improvements noted according to physician assessment and chromometer erythema index. Statistically significant improvements between the two sides were first noted on day 4. Conclusion: Treatment using a 635-nm-wavelength LED array decreases the intensity and duration of post-fractional CO2 laser treatment erythema.
Article
Angiogenesis is a key process for wound healing. There are few reports of LED phototherapy on angiogenesis, mainly in vivo. The aim of the present investigation was to evaluate histologically the angiogenesis on dorsal cutaneous wounds treated with laser (660 and 790 nm) or LEDs (700, 530, and 460 nm) in a rodent model. Twenty-four young adult male Wistar rats weighting between 200 and 250 g were used on the present study. Under general anesthesia, one excisional wound was created on the dorsum of each animal that were then randomly distributed into six groups with four animals each: G0-control; G1-laser λ660 nm (60 mW, ϕ ∼2 mm, 10 J/cm(2)); G2-laser λ790 nm (50 mW, ϕ ∼2 mm, 10 J/cm(2)); G3-LED λ700 ± 20 nm (15 mW, ϕ ∼16 mm, 10 J/cm(2)); G4-LED λ530 ± 20 nm (8 mW, ϕ ∼16 mm, 10 J/cm(2)); G5-LED λ460 ± 20 nm (22 mW, ϕ ∼16 mm, 10 J/cm(2)). Irradiation started immediately after surgery and was repeated every other day for 7 days. Animal death occurred at the eighth day after surgery. The specimens were removed, routinely processed to wax, cut and stained with HE. Angiogenesis was scored by blood vessel counting in the wounded area. Quantitative results showed that green LED (λ530 ± 20 nm), red LED (λ700 ± 20 nm), λ790 nm laser and λ660 nm laser caused significant increased angiogenesis when compared to the control group. It is concluded that both laser and LED light are capable of stimulating angiogenesis in vivo on cutaneous wounds and that coherence was not decisive on the outcome of the treatment.
Article
Photobiomodulation with near infrared light (NIR) provides cellular protection in various disease models. Previously, infrared light emitted by a low-energy laser has been shown to significantly improve recovery from ischemic injury of the canine heart. The goal of this investigation was to test the hypothesis that NIR (670 nm) from light emitting diodes produces cellular protection against hypoxia and reoxygenation-induced cardiomyocyte injury. Additionally, nitric oxide (NO) was investigated as a potential cellular mediator of NIR. Our results demonstrate that exposure to NIR at the time of reoxygenation protects neonatal rat cardiomyocytes and HL-1 cells from injury, as assessed by lactate dehydrogenase release and MTT assay. Similarly, indices of apoptosis, including caspase 3 activity, annexin binding and the release of cytochrome c from mitochondria into the cytosol, were decreased after NIR treatment. NIR increased NO in cardiomyocytes, and the protective effect of NIR was completely reversed by the NO scavengers carboxy-PTIO and oxyhemoglobin, but only partially blocked by the NO synthase (NOS) inhibitor L-NMMA. Mitochondrial metabolism, measured by ATP synthase activity, was increased by NIR, and NO-induced inhibition of oxygen consumption with substrates for complex I or complex IV was reversed by exposure to NIR. Taken together these data provide evidence for protection against hypoxia and reoxygenation injury in cardiomyocytes by NIR in a manner that is dependent upon NO derived from NOS and non-NOS sources.
Article
Background: It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of "invasive" and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles. Methods: Denervated gastrocnemius muscles of toads were irradiated with He-Ne laser (6.0 mW, 31.2 J/cm2) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone. Results: The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 +/- 4% and 6 +/- 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 +/- 2% and 11 +/- 2%, respectively) in the control muscles. The young myofibres populated 34 +/- 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 +/- 2%) in control denervated muscles. Conclusions: It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are "recruited" and participate in the process of regeneration.
Article
Background and Objectives Inhibition of cyclooxygenase (COX) and prostaglandin E2 (PGE2) protects cells against cell injury in specific pathophysiological situations: inflammation and oxidative stress. Although the anti-inflammatory effects have been reported in clinical fields for specific wavelength irradiation during wound healing, the physiological mechanism has not been clarified yet. The aim of the present study is to investigate the anti-inflammatory mechanism of 635 nm light-emitting-diode (LED) irradiation compared with existing COX inhibitors.Study Design/Materials and Methods The present study investigated anti-inflammatory effects of 635 nm irradiation on PGE2 release, COX and phospholipase A2 (PLA2) expression, and reactive oxygen species (ROS) dissociation in arachidonic acid (AA)-treated human gingival fibroblast (hGF). These results were compared with their existing COX inhibitors: indomethacin and ibuprofen. The PGE2 release was measured by enzyme immunoassay, the COX expression was measured by western blot and reverse transcriptase polymerase chain reaction (RT-PCR), and ROS level was measured by flow cytometry, laser scanning confocal microscope and RT-PCR.ResultsResults showed that 635 nm irradiation and existing COX inhibitors inhibit expression of COX and PGE2 release. Unlike indomethacin and ibuprofen, 635 nm irradiation leads to a decrease of ROS levels and mRNA expression of cytosolic phospholipase A2 (cPLA2) and secretary phospholipase A2 (sPLA2).Conclusion Taken together, 635 nm irradiation, unlike indomethacin and ibuprofen, can directly dissociate the ROS. This inhibits cPLA2, sPLA2, and COX expression, and results in the inhibition of PGE2 release. Thus, we suggest that 635 nm irradiation inhibits PGE2 synthesis like COX inhibitor and appears to be useful as an anti-inflammatory tool. Lesers Surg. Med. 39:614–621, 2007. © 2007 Wiley-Liss, Inc.
Article
We previously reported that 710 nm Light-emitting Diode (LED) has a protective effect through cellular immunity activation in the stroke animal model. However, whether LED directly protects neurons suffering from neurodegeneration was entirely unknown. Therefore, we sought to determine the effects of 710 nm visible light irradiation on neuronal protection and neuronal outgrowth in an in vitro stroke model. Primary cultured rat cortical neurons were exposed to oxygen-glucose deprivation (OGD) and reoxygenation and normal conditions. An LED array with a peak wavelength of 710 nm was placed beneath the covered culture dishes with the room light turned off and were irradiated accordingly. LED treatments (4 min at 4 J/cm(2) and 50 mW/cm(2)) were given once to four times within 8h at 2h intervals for 7 days. Mean neurite density, mean neurite diameter, and total fiber length were also measured after microtubule associated protein 2 (MAP2) immunostaining using the Axio Vision program. Synaptic marker expression and MAPK activation were confirmed by Western blotting. Images captured after MAP2 immunocytochemistry showed significant (p<0.05) enhancement of post-ischemic neurite outgrowth with LED treatment once and twice a day. MAPK activation was enhanced by LED treatment in both OGD-exposed and normal cells. The levels of synaptic markers such as PSD 95, GAP 43, and synaptophysin significantly increased with LED treatment in both OGD-exposed and normal cells (p<0.05). Our data suggest that LED treatment may promote synaptogenesis through MAPK activation and subsequently protect cell death in the in vitro stroke model.
Article
Difficulties of quantitation of hemoglobin/myoglobin absorption changes in muscle have led to the development of a new approach using short pulses of light. This method uses input light pulses sufficiently short so that the time course of travel of light through the brain can be precisely measured. The time of arrival of light at the detector gives the optical path length, given the velocity of light in tissues. The intensity profile of photon migration in tissues permits determination of the path length that the exiting photons have traveled and the concentration change of the pigments. A cavity-dumped liquid dye laser illuminates the tissue with 130-ps pulses detected as 600-ps duration at a half height at 3.0-cm distance from the input point. The decay of intensity from the 50% point onward to 0.1% follows a logarithmic function of slope μ which is attributed to the total absorption coefficient of the tissue. Increments of μ due to deoxyhemoglobin absorption at 760 and 630 nm are used to calculate the concentration change. This permits the calculation of the path length for continuous light measurements of 2 cm for a particular geometry. Variation of the wavelength of the laser affords determination of a spectrum of changes in the tissue.