Wavelength and dose-dependent effects of photobiomodulation therapy on wound healing in rat model

Abstract

Photobiomodulation therapy (PBMT) is the use of near infrared light to stimulate tissue repair in the healing process. The aim of this study was to evaluate the wavelength- and dose-dependent effects of PBMT on wound healing. Thirty-six Sprague Dawley rats with four circular full thickness 6 mm diameter cutaneous wounds each were distributed into experimental part 1 for optimization of wavelengths on wound treatment and experimental part 2 for dose-dependent studies. In part 1, various near infrared laser wavelengths (808, 880 and 1064 nm) were used as PBMT light source to optimize the wound treatment under the same fluence of 5 J cm-2. Furthermore, the optimal wavelength was selected as treatment source in part 2 with various power densities in the range of 20-100 mW cm-2. All wounds were treated immediately except for the control group and the experiment was conducted for nine consecutive days. The result in part 1 showed that 808 nm was the optimal wavelength to give the highest wound closure percentage at 94.08% ± 6.5%, meanwhile power density of 40-60 mW cm-2 better accelerated the healing rate than other groups in part 2. Therefore, PBMT using 808 nm at the range of 40-60 mW cm-2 has beneficial effects on the wound healing process.