Low intensity laser therapy effectiveness in controlling neuropathic pain in mice

La terapia láser de baja potencia (LLLT) ha sido ampliamente discutida en la literatura como forma alternativa de tratamiento para muchos tipos de dolor, especialmente para el neuropático. Esa terapia se destaca por el hecho de no ser invasiva, raramente causar efectos secundarios y ser de bajo costo. En cambio, para su eficacia, es necesario que se presenten los detalles de los parámetros, que todavía son muy discordantes en la literatura. Así, este trabajo tiene como objetivo investigar el efecto de la LLLT, en el rango del infrarrojo, con fluidez de 30 J/cm², en el control del dolor neuropático en modelos animales. Se utilizaron 24 ratones de la cepa suizo-albino, machos, con peso de 2530 gramos, divididos en tres grupos: Grupo Placebo (GP), Grupo Láser (GL30) y Grupo Sham (GS). Se llevó a cabo la inducción de la neuropatía por medio del modelo de constricción crónica del nervio isquiático y se realizó el tratamiento de la LLLT como sigue: GP con el láser con fluidez de 0 J/cm2, GL30 con fluidez de 30 J/cm2, y GS con simulación de cirugía sin intervención. Se realizaron las irradiaciones tres veces por semana, durante 90 días, en el punto de compresión del nervio, utilizándose la técnica de contacto. A efectos de evaluación, se utilizaron la prueba de placa caliente para hiperalgesia térmica y la prueba de Randall y Selitto para hiperalgesia mecánica. En los resultados del GP, observamos que no hubo mejora significativa en los días después de la cirugía en ninguna de las pruebas realizadas y, en el GP30, se verificó mejora significativa en ambas pruebas: desde el 30.º día de tratamiento para la prueba de placa caliente y desde el 45.º día para la prueba de Randall y Selitto, en que los ratones presentaron restauración total de la sensibilidad. Concluimos, por lo tanto, que el uso de la LLLT con fluidez de 30 J/cm2 en el tratamiento del dolor neuropático en modelos animales es efectivo.Low-level laser therapy (LLLT) has been widely discussed in the literature as an alternative form of treatment for several types of pain, especially neuropathic pain. This kind of therapy stands out for not being invasive, rarely causing side effects and being cost effective. However, for its effectiveness, it is necessary more detailed parameters, which are still very discrepant in the literature. Thus, this study aims to investigate the effect of LLLT, in the infrared range, with 30J/cm² fluency, on the control of neuropathic pain in animal models. A total of 24 male Swiss albino mice, weighing 25.30 grams, were divided into three groups: the Control Group (CG), the Laser Group (L30G) and the Sham Group (SG). The induction of neuropathy was held through the model of chronic constriction of the sciatic nerve (CCI), and the LLLT treatment was conducted as follows: The CG was treated with 0 J/cm2 fluency, whereas the L30G was treated with 30 J/cm2 fluency, and the SG with simulation of surgery without intervention. The irradiations were performed 3 times a week, for 90 days, at the nerve’s point of compression, using the contact technique. For the evaluation, the Hot Plate Test was used for thermal hyperalgesia, and the Randall-Selitto test was used for mechanical hyperalgesia. In the CG’s results, we observed no significant improvement in the days after surgery in any of the tests conducted, and, in the GL30, a significant improvement in both tests was observed: from the 30th day of treatment for the Hot Plate Test, and from the 45th for the Randall-Selitto Test, in which the mice showed total restoration of sensitivity. We thus conclude that the use of LLLT with 30 J/cm2 fluency in the treatment of neuropathic pain in animal models is effective.A terapia a laser de baixa intensidade (LLLT) vem sendo amplamente discutida na literatura como forma alternativa de tratamento para diversos tipos de dor, com destaque para a neuropática. Essa terapia sobressai pelo fato de não ser invasiva, raramente causar efeitos colaterais e ser de baixo custo. Em contrapartida, para sua eficácia, é necessário o detalhamento dos parâmetros, que ainda são muito discrepantes na literatura. Assim, este trabalho tem como objetivo investigar o efeito da LLLT, na faixa do infravermelho, com fluência de 30J/cm², no controle da dor neuropática em modelo animal. Foram utilizados 24 camundongos da cepa suíço albino, machos, pesando 25­30 gramas, divididos em três grupos: Grupo Placebo (GP), Grupo Laser (GL30) e Grupo Sham (GS). A indução da neuropatia foi feita através do modelo de constrição crônica do nervo isquiático (CCI), e o tratamento da LLLT realizou-se da seguinte maneira: GP com o laser com fluência de 0J/cm2, GL30 tratado com fluência de 30J/cm2, e GS com simulação de cirurgia sem intervenção. Executaram-se as irradiações 3 vezes por semana, durante 90 dias, no ponto de compressão do nervo, utilizando-se a técnica de contato. A fins de avaliação, foram utilizados o teste da placa quente, para hiperalgesia térmica, e o Teste de Randall-Selitto para hiperalgesia mecânica. Nos resultados do GP, observamos que não houve melhora significativa nos dias após a cirurgia em nenhum dos testes realizados e, no GL30, observou-se uma melhora expressiva em ambos os testes a partir do 30º dia de tratamento para o teste de Placa Quente e a partir do 45º para o Randall-Selitto, em que os camundongos apresentaram restauração total da sensibilidade. Concluímos, pois, que a utilização de LLLT com fluência de 30J/cm2 no tratamento da dor neuropática em modelo animal é eficaz

Time response of increases in ATP and muscle resistance to fatigue after low-level laser (light) therapy (LLLT) in mice

Recently, low-level laser (light) therapy has been used to increase muscle performance in intense exercises. However, there is a lack of understanding of the time response of muscles to light therapy. The first purpose of this study was to determine the time response for light-emitting diode therapy (LEDT)-mediated increase in adenosine triphosphate (ATP) in the soleus and gastrocnemius muscles in mice. Second purpose was to test whether LEDT can increase the resistance of muscles to fatigue during intense exercise. Fifty male Balb/c mice were randomly allocated into two equal groups: LEDT-ATP and LEDT-fatigue. Both groups were subdivided into five equal subgroups: LEDT-sham, LEDT-5 min, LEDT-3 h, LEDT-6 h, and LEDT-24 h. Each subgroup was analyzed for muscle ATP content or fatigue at specified time after LEDT. The fatigue test was performed by mice repeatedly climbing an inclined ladder bearing a load of 150 % of body weight until exhaustion. LEDT used a cluster of LEDs with 20 red (630 ± 10 nm, 25 mW) and 20 infrared (850 ± 20 nm, 50 mW) delivering 80 mW/cm[superscript 2] for 90 s (7.2 J/cm[superscript 2]) applied to legs, gluteus, and lower back muscles. LEDT-6 h was the subgroup with the highest ATP content in soleus and gastrocnemius compared to all subgroups (P < 0.001). In addition, mice in LEDT-6 h group performed more repetitions in the fatigue test (P < 0.001) compared to all subgroups: LEDT-sham and LEDT-5 min (~600 %), LEDT-3 h (~200 %), and LEDT-24 h (~300 %). A high correlation between the fatigue test repetitions and the ATP content in soleus (r = 0.84) and gastrocnemius (r = 0.94) muscles was observed. LEDT increased ATP content in muscles and fatigue resistance in mice with a peak at 6 h. Although the time response in mice and humans is not the same, athletes might consider applying LEDT at 6 h before competition.National Institutes of Health (U.S.) (grant R01AI050875

Low-level laser therapy (808 nm) contributes to muscle regeneration and prevents fibrosis in rat tibialis anterior muscle after cryolesion

Muscle regeneration is a complex phenomenon, involving replacement of damaged fibers by new muscle fibers. During this process, there is a tendency to form scar tissue or fibrosis by deposition of collagen that could be detrimental to muscle function. New therapies that could regulate fibrosis and favor muscle regeneration would be important for physical therapy. Low-level laser therapy (LLLT) has been studied for clinical treatment of skeletal muscle injuries and disorders, even though the molecular and cellular mechanisms have not yet been clarified. The aim of this study was to evaluate the effects of LLLT on molecular markers involved in muscle fibrosis and regeneration after cryolesion of the tibialis anterior (TA) muscle in rats. Sixty Wistar rats were randomly divided into three groups: control, injured TA muscle without LLLT, injured TA muscle treated with LLLT. The injured region was irradiated daily for four consecutive days, starting immediately after the lesion using an AlGaAs laser (808 nm, 30 mW, 180 J/cm[superscript 2]; 3.8 W/cm[superscript 2], 1.4 J). The animals were sacrificed on the fourth day after injury. LLLT significantly reduced the lesion percentage area in the injured muscle (p < 0.05), increased mRNA levels of the transcription factors MyoD and myogenin (p < 0.01) and the pro-angiogenic vascular endothelial growth factor (p < 0.01). Moreover, LLLT decreased the expression of the profibrotic transforming growth factor TGF-β mRNA (p < 0.01) and reduced type I collagen deposition (p < 0.01). These results suggest that LLLT could be an effective therapeutic approach for promoting skeletal muscle regeneration while preventing tissue fibrosis after muscle injury.National Institutes of Health (U.S.) (grant R01AI050875)Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorConselho Nacional de Pesquisas (Brazil)Fundação de Amparo à Pesquisa do Estado de São Paul

Characterization and in Vivo Biological Performance of Biosilicate

After an introduction showing the growing interest in glasses and glass-ceramics as biomaterials used for bone healing, we describe a new biomaterial named Biosilicate. Biosilicate is the designation of a group of fully crystallized glass-ceramics of the Na2O-CaO-SiO2-P2O5 system. Several in vitro tests have shown that Biosilicate is a very active biomaterial and that the HCA layer is formed in less than 24 hours of exposure to simulated body fluid (SBF) solution. Also, in vitro studies with osteoblastic cells have shown that Biosilicate disks supported significantly larger areas of calcified matrix compared to 45S5 Bioglass, indicating that this bioactive glass-ceramic may promote enhancement of in vitro bone-like tissue formation in osteogenic cell cultures. Finally, due to its special characteristics, Biosilicate has also been successfully tested in several in vivo studies. These studies revealed that the material is biocompatible, presents excellent bioactive properties, and is effective to stimulate the deposition of newly formed bone in animal models. All these data highlight the huge potential of Biosilicate to be used in bone regeneration applications.Universidade Federal de São Paulo, Dept Biosci, BR-11060001 Santos, SP, BrazilUniv Fed Sao Carlos, Dept Mat Engn, Vitreous Mat Lab, BR-13565905 Sao Carlos, SP, BrazilUniv Fed Sao Carlos, Dept Physiotherapy, BR-13565905 Sao Carlos, SP, BrazilUniversidade Federal de São Paulo, Dept Biosci, BR-11060001 Santos, SP, BrazilWeb of Scienc

Light-emitting diode therapy (LEDT) before matches prevents increase in creatine kinase with a light dose response in volleyball players

Low-level laser (light) therapy (LLLT) has been applied over skeletal muscles before intense exercise (muscular pre-conditioning) in order to reduce fatigue and muscle damage (measured by creatine kinase, CK) in clinical trials. However, previous exercise protocols do not exactly simulate the real muscle demand required in sports. For this reason, the aim of this randomized and double-blind placebo-controlled trial was to investigate whether light-emitting diode therapy (LEDT) applied over the quadriceps femoris muscles, hamstrings, and triceps surae of volleyball players before official matches could prevent muscle damage (CK) with a dose response, establishing a therapeutic window. A professional male volleyball team (12 athletes) was enrolled in this study, and LEDT was applied before 4 matches during a national championship. LEDT used an array of 200 light-emitting diodes (LEDs) arranged in 25 clusters of 4 infrared LEDs (850 ± 20 nm; 130 mW) and 25 clusters of 4 red LEDs (630 ± 10 nm; 80 mW). Athletes were randomized to receive one of four different total doses over each muscle group in a double-blind protocol: 105 J (20 s), 210 J (40 s), 315 J (60 s), and placebo (no light for 30 s). CK in blood was assessed 1 h before and 24 h after each match. LEDT at 210 J avoided significant increases in CK (+10 %; P = 0.993) as well as 315 J (+31 %, P = 0.407). Placebo (0 J) allowed a significant increase in CK (+53 %; P = 0.012) as well as LEDT at 105 J (+59 %; P = 0.001). LEDT prevented significant increases of CK in blood in athletes when applied before official matches with a light dose response of 210–315 J, suggesting athletes might consider applying LEDT before competition.National Institutes of Health (U.S.) (Grant R01AI050875

Morphological aspects and Cox-2 expression after exposure to 780-nm laser therapy in injured skeletal muscle: an in vivo study

Background:The effectiveness of low-level laser therapy in muscle regeneration is still not well known. Objective: To investigate the effects of laser irradiation during muscle healing.Method: For this purpose, 63 rats were distributed to 3 groups: non-irradiated control group (CG); group irradiated at 10 J/cm² (G10); and group irradiated at 50 J/cm² (G50). Each group was divided into 3 different subgroups (n=7), and on days 7, 14 and 21 post-injury the rats were sacrificed.Results:Seven days post-surgery, the CG showed destroyed zones and extensive myofibrillar degeneration. For both treated groups, the necrosis area was smaller compared to the CG. On day 14 post-injury, treated groups demonstrated better tissue organization, with newly formed muscle fibers compared to the CG. On the 21st day, the irradiated groups showed similar patterns of tissue repair, with improved muscle structure at the site of the injury, resembling uninjured muscle tissue organization. Regarding collagen deposition, the G10 showed an increase in collagen synthesis. In the last period evaluated, both treated groups showed statistically higher values in comparison with the CG. Furthermore, laser irradiation at 10 J/cm2 produced a down-regulation of cyclooxygenase 2 (Cox-2) immunoexpression on day 7 post-injury. Moreover, Cox-2 immunoexpression was decreased in both treated groups on day 14.Conclusions:Laser therapy at both fluencies stimulated muscle repair through the formation of new muscle fiber, increase in collagen synthesis, and down-regulation of Cox-2 expression.Universidade Federal de São Carlos Departamento de FisioterapiaUniversidade Estadual de Campinas Faculdade de Ciências Médicas Departamento de CirurgiaUniversidade de São Paulo Departamento de Biomecânica, Medicina e Reabilitação do Sistema LocomotorUniversidade Federal de São Paulo (UNIFESP) Departamento de BiociênciasUNIFESP, Depto. de BiociênciasSciEL

Aplicações da imagem termográfica infravermelha no cuidado ao recém-nascido prematuro: uma revisão de escopo: Applications of infrared thermographic imaging in the care of premature newborns: a scoping review

Objetivo: Avaliar a extensão na literatura quanto ao uso da Termografia Infravermelha como método alternativo no cuidado ao recém-nascidos pré-termos. Métodos: Trata-se de uma revisão de escopo, realizada mediante nas buscas em bases de dados eletrônicas: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE via PubMed, LILACS, Theses Database e ClinicalTrials.gov. Resultados: 11 artigos foram considerados elegíveis, e dentre as aplicações da Termografia Infravermelha estavam: investigação da temperatura da superfície corporal e padrões de distribuições de temperatura, mensuração/avaliação de gasto energético e monitoramento respiratório. Conclusões: O uso da Termografia Infravermelha é uma ótima alternativa em comparação aos métodos convencionais utilizados na prática clínica, podendo ser utilizada para diferentes aplicações no cuidado ao recém-nascido prematuro. Contudo, a escassez de estudos a respeito do tema e as várias limitações apresentadas nas publicações encontradas, mostram a necessidade do desenvolvimento e condução de novos estudos, com protocolos metodológicos bem estabelecidos e detalhados

Bacterial cellulose-based biomaterials on third-degree burns in rats

Burns are cutaneous lesions that present  high rate of morbidity and mortality worldwide. In order to innovate the treatment strategies currently applied new biomaterials are being investigated. The aim of the present study was to evaluate the action of bacterial cellulose in both membrane and gel form, in the treatment of third degree burns in rats. For this, 24 Wistar rats were used, divided into three distinct groups. The lesion was performed with the aid of a soldering iron heated at 150 °C pressed on the back of the animal for 10 seconds. Treatment was performed immediately after wound induction, and skin samples were collected on the tenth day post-injury. Statistical analysis was performed using a significance level of 5% (p?0.05). The histological results show differences in the healing process presented by each group. The group that received bacterial cellulose in the membrane format presented the best results, such as discrete inflammatory infiltrate and better morphological quality of the tissue, characterizing an advanced stage of the healing process, also proven in the collagen quantitative analysis. On the other hand, the group that received the cellulose gel showed characteristics of an inflammatory phase with the presence of evident ulcerations, which corresponds to a delay in the healing process even when compared to CG alone. Thus, it was concluded that before the biomaterials tested cellulose membrane in the format presented more favorable results both in terms of environmental protection as a contribution to an adequate tissue recovery.

Low-level laser therapy (LLLT) combined with swimming training improved the lipid profile in rats fed with high-fat diet

Obesity and associated dyslipidemia is the fastest growing health problem throughout the world. The combination of exercise and low-level laser therapy (LLLT) could be a new approach to the treatment of obesity and associated disease. In this work, the effects of LLLT associated with exercises on the lipid metabolism in regular and high-fat diet rats were verified. We used 64 rats divided in eight groups with eight rats each, designed: SC, sedentary chow diet; SCL, sedentary chow diet laser, TC, trained chow diet; TCL, trained chow diet laser; SH, sedentary high-fat diet; SHL, sedentary high-fat diet laser; TH, trained high-fat diet; and THL, trained high-fat diet laser. The exercise used was swimming during 8 weeks/90 min daily and LLLT (GA-Al-As, 830 nm) dose of 4.7 J/point and total energy 9.4 J per animal, applied to both gastrocnemius muscles after exercise. We analyzed biochemical parameters, percentage of fat, hepatic and muscular glycogen and relative mass of tissue, and weight percentage gain. The statistical test used was ANOVA, with post hoc Tukey–Kramer for multiple analysis between groups, and the significant level was p < 0.001, p < 0.01, and p < 0.05. LLLT decreased the total cholesterol (p < 0.05), triglycerides (p < 0.01), low-density lipoprotein cholesterol (p < 0.05), and relative mass of fat tissue (p < 0.05), suggesting increased metabolic activity and altered lipid pathways. The combination of exercise and LLLT increased the benefits of exercise alone. However, LLLT without exercise tended to increase body weight and fat content. LLLT may be a valuable addition to a regimen of diet and exercise for weight reduction and dyslipidemic control