Abstract

This study aimed to investigate the effects of PBMT with a synergistic combination of lasers and light emitting diodes (LEDs) with three different wavelengths and three doses on cytochrome c oxidase activity in intact skeletal muscle, and also to determine the time-window between irradiation and increased activity on cytochrome c-oxidase in skeletal muscle fibers. Male Wistar rats (240 ± 20g) were divided into two groups (placebo and PBMT) where seven different experimental time-points were tested. Transcutaneous PBMT was irradiated at tibialis anterior muscles employing a cluster with 9 diodes (1 laser diode of 905nm, 4 LED diodes of 875nm, 4 LED diodes of 640nm – manufactured by Multi Radiance Medical™), with different doses (1, 3 and 10 J). Then muscles were removed at different experimental time-points (5, 10, 30 minutes, 1, 2, 12 and 24 hours) and the analyses of cytochrome c oxidase expression were performed by immunohistochemistry. PBMT with 10 J dose increased cytochrome coxidase expression with significant difference (p<0.05) when compared to the placebo group at all time-points tested. The 3 J dose showed significant differences (p<0.05) when compared to the placebo group from 30 mins to 12 h time-points, and the 1J dose showed significant differences (p<0.05) when compared to the placebo group from 30 mins to 24 h. PBMT with the combination of super-pulsed laser, red and infrared LEDs can increase cytochrome c-oxidase activity in intact skeletal muscle mainly with 10 J dose fulfilling the time-response window from 5 minutes until 24 hours after irradiation.

© 2019 SPIE/OSA