The Ability of Low Level Laser Therapy to Prevent Muscle Tissue Damage Induced by Snake Venom

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Antivenom therapy has been ineffective in neutralizing the severe local fast developing tissue damage following snakebite envenoming. Herein, some effects of in situ helium neon (HeNe) laser irradiation on rat nerve-muscle preparation injected with Bothrops jararacussu venom are described. The tibialis anterior muscle was injected with venom diluted in 0.9% saline solution (60 mu g/0.02 mL) or saline solution alone. Sixty minutes after venom injection, laser (HeNe) treatment was administered at three incident energy densities: dose 1, a single exposure of 3.5 J cm(-2); dose 2, three exposures of 3.5 J cm(-2); dose 3, a single exposure of 10.5 J cm(-2). Muscle function was assessed through twitch tension recordings whereas muscle damage was evaluated through histopathologic analysis, morphometry of area of tissue affected and creatine kinase (CK) serum levels, and compared to unirradiated muscles. Laser application at the dose of 3.5 J cm(-2) reduced the area of injury by 64% (15.9 +/- 1.5%vs 44.2 +/- 5.7%), decreased the neuromuscular blockade (NMB) by 62% (11.5 +/- 2.5%vs 30.4 +/- 5.2%) and reduced CK levels by 58% (from 455 +/- 4.5% to 190.3 +/- 23.4%) when compared with unirradiated controls. Dose 2 showed a poorer benefit than dose 1, and dose 3 was ineffective in preventing the venom effects. Measurements of the absorbance of unirradiated and irradiated venom solution showed no difference in absorption spectra. In addition, no difference in the intensity of partial NMB in nerve-muscle preparation was shown by unirradiated and irradiated venom. The results indicate that the laser light did not alter venom toxicity. We conclude that HeNe laser irradiation at a dosage of 3.5 J cm(-2) effectively reduces myonecrosis and the neuromuscular transmission blocking effect caused by B. jararacussu snake venom. Thus, low level laser therapy may be a promising tool to minimize the severity of some of the local effects of snake envenoming.8516369Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Laserterapia de baixa intensidade na expressão de colágeno após lesão muscular cirúrgica Low-level laser therapy in the expression of collagen after muscular surgical injury

A laserterapia é um procedimento utilizado em larga escala nas lesões musculoesqueléticas, devido as suas diversas propriedades, antiinflamatórias, cicatrizantes entre outras. Além disso, há tipos distintos de aparelhos de laser. Mesmo com os diversos modelos experimentais existentes na literatura, não há um consenso sobre a faixa de utilização, bem como o tipo de laser que promove melhor reparo no tecido muscular. Este estudo visa analisar os efeitos da laserterapia de baixa intensidade na expressão de colágeno após lesão muscular. Camundongos Swiss albinos (n=18) foram submetidos à lesão muscular cirúrgica e divididos em dois grupos, controle (C) e teste (T). Os animais foram submetidos a uma irradiação diária de 5 J/cm² pelos lasers AsGaAl 830 nm e AsGa 904 nm e, em diferentes tempos de sacrifício (7 e 14 dias). Os resultados não demonstraram diferença estatística significativa na expressão de colágeno em ambos os grupos analisados. Contudo, os dados apontam que a dose de 5 J/cm² do laser AsGa 904 nm promoveu maior deposição de fibras colágenas após 14 dias de tratamento, sugerindo que a terapia seja efetiva na síntese de colágeno. Outros estudos experimentais, em humanos, devem ser propostos para maiores inferências sobre os resultados do laser no tratamento da lesão muscular.<br>The laser therapy is a procedure utilized at long scale in the musculoskeletal injuries, due its anti-inflammatory and reparatory proprieties and others. Besides, there are differents types of laser equipments. Despites with the many experimental models at literature, there is no consensus about the range of application as well as the type of laser that promove of the best repair in muscular tissue. The aim of this study is to analyze the effects of the low level laser therapy in the expression of collagen after muscular injury. Mice Swiss albinos (n=18) were subjected to the muscular surgical injury and separated in two groups, control (C) and test (T). The animals were submitted a daily radiation of 5 J/cm² for the lasers AsGaAl 830 nm and AsGa 904 nm and, in different times of sacrifice (7 and 14 days). The results didn't demonstrate significant statistical difference in the expression of collagen in both analyzed groups. However, the data appear that the dose of 5 J/cm² of the laser AsGa 904 nm promoted larger deposition of fibers collagens after 14 days of treatment, suggesting that the therapy is effective in the synthesis of collagen. Others studies will be proposed at humans to bigger inferences about the results of laser in the treatment muscular injury