Analgesic Effect of Light-Emitting Diode (LED) Therapy at Wavelengths of 635 and 945 nm on Bothrops moojeni Venom-Induced Hyperalgesia

Envenoming induced by Bothrops snakes is characterized by drastic local tissue damage involving hemorrhage, myonecrosis and proeminent inflammatory and hyperalgesic response. The most effective treatment is antivenom therapy, which is ineffective in neutralizing the local response. Herein, it was evaluated the effectiveness of light-emitting diode (LED) at wavelengths of 635 and 945nm in reducing inflammatory hyperalgesia induced by Bothrops moojeni venom (BmV) in mice, produced by an subplantar injection of BmV (1g). Mechanical hyperalgesia and allodynia were assessed by von Frey filaments at 1, 3, 6 and 24h after venom injection. The site of BmV injection (1.2cm(2)) was irradiated by LEDs at 30min and 3h after venom inoculation. Both 635nm (110mW, fluence of 3.76J/cm(2) and 41s of irradiation time) and 945nm (120mW, fluence of 3.8J/cm(2) and 38s of irradiation time) LED inhibited mechanical allodynia and hyperalgesia of mice alone or in combination with antivenom treatment, even when the symptoms were already present. The effect of phototherapy in reducing local pain induced by BmV should be considered as a novel therapeutic tool for the treatment of local symptoms induced after bothropic snake bites.