Effects of photobiostimulation on edema and hemorrhage induced by Bothrops moojeni venom.

Antivenom (AV) treatment has been ineffective in neutralizing the severe local fast-developing tissue damage following snake-bite envenoming. We studied the effectiveness of low-level laser (LLL) and light-emitting diode (LED) irradiation alone or in combination with AV in reducing local edema formation and hemorrhage induced by Bothrops moojeni venom (BmV) in mice. Edema formation was induced by injection of 1 μg per paw of BmV into the right paw and was evaluated before and at several intervals after BmV intraplantar injection. Hemorrhagic activity was evaluated after intradermal injection of 20 μg of BmV by measuring the diameter of the hemorrhagic area on the inner side of the skin. The site of BmV injection was irradiated by LLL or LED 30 min after BmV inoculation. AV was also administered intravenously 30 min after BmV injection. Irradiation with LLL at a wavelength of 685 nm and a dose of 2.2 J/cm(2) and with a red LED and an infrared LED at wavelengths of 635 nm and 945 nm, respectively, and a dose of 4 J/cm(2) reduced edema formation and hemorrhage induced by BmV (p < 0.05). The combined AV and LLL or LED treatment showed the same reduction as LLL or LED irradiation separately. In conclusion, both LLL and LED irradiation reduced venom-induced local effects even though symptoms were already present. Thus, the effect of phototherapy in reducing local effects induced by BmV may be clinically relevant.