The aim of the study was to investigate the biochemical and molecular changes in the process of epidermal healing of burn injuries after therapeutic treatment with low-power laser (LPL) and light-emitting diode (LED). Rats were divided into six groups: skin without injury (Sham), burn wounds (BWs), BW + 660-nm LPL, BW + 904-nm LPL, BW + 632-nm LED, and BW + 850-nm LED. The burn wound model was performed using a 100 °C copper plate, with 10 s of contact in the skin. The irradiations started 24 h after the lesion and were performed daily for 7 days. The burn wound groups showed an increase in the superoxide production, dichlorofluorescein, nitrites, and high protein oxidative damage. The activities of glutathione peroxidase and catalase were also increased, and a significant reduction in glutathione levels was observed compared to the control group. However, treatments with 660-nm LPL and 850-nm LED promoted protection against to oxidative stress, and similar results were also observed in the IL-6 and pERK1/2 expression. Taken together, these results suggest that LPL 660 nm and LED 850 nm appear reduced in the inflammatory response and oxidative stress parameters, thus decreasing dermal necrosis and increasing granulation tissue formation, in fact accelerating the repair of burn wounds.
Keywords: LED; dermal burn lesion; inflammation; low-power laser; oxidative stress.