Effect of low-level laser therapy in the myonecrosis induced by Bothrops jararacussu snake venom.

Objective: The aim of this work was to investigate the capacity of low-level laser therapy (LLLT) alone or in combination with antivenom (AV) to reduce myonecrosis induced by Bothrops jararacussu snake venom.

Background Data: Myonecrosis is the most pronounced local effect caused by B. jararacussu venom. AV therapy and other first-aid treatments do not reverse these local effects.

Material And Methods: Male Swiss mice were used. Myonecrosis was induced by injection of 0.6 mg/kg of B. jararacussu venom in the right gastrocnemius muscle and was evaluated at 3 or 24 h after venom injection. The site of venom administration was irradiated for 29 s with a low power semiconductor laser (685 nm) at a dose of 4.2 J/cm(2). Intravenous AV therapy (0.5 mL dose) was administered at different times: 30 min before venom injection or 0, 1, or 3 h afterward. Both AV therapy and LLLT treatments were duplicated in mice groups killed at 3 or 24 h.

Results: B. jararacussu venom caused a significant myonecrotic effect 3 and 24 h after venom injection. LLLT significantly reduced myonecrosis by 83.5% at 24 h (p < 0.05) but not at 3 h, and AV therapy alone was ineffective for reducing myonecrosis at 3 and 24 h.

Conclusion: Only LLLT significantly reduced myonecrosis of the envenomed muscle, suggesting that LLLT is a potentially therapeutic approach for treating the local effects of B. jararacussu venom.