Effect of Pulsed 810 nm Laser Photobiomodulation on Dermal Wound Healing and Oxidative Stress in Immunosuppressed Rats

Abstract

Under immunosuppression, the sequential overlapping wound repair phases get hampered due to dysregulated or persistent inflammation leading to non-healing chronic wounds formation. The present study investigates the effect of low-power 810 nm diode laser (70 mW mean output power; 40 mW/cm2 average irradiance; 24 J/cm2 total fluence; 10 Hz pulse frequency; duty cycle 50 per cent; 10 min. illumination time once daily for seven days) photobiomodulation (PBM) on dermal penetration ability, wound healing and oxidative stress in hydrocortisone-induced immunosuppressed rats. The results of the penetration ability of 810 nm laser irradiation to the depth of the sub-dermal region revealed that the transmitted power of laser at 10 Hz pulsed-mode was better and easier than continuous-mode. The present findings clearly delineated that PBM with 810 nm laser at 10 Hz significantly augmented healing and reduced oxidative stress as evidenced by decreased free radicals, nitric oxide (NO) levels, enhanced superoxide dismutase (SOD) enzyme activity and wound area contraction facilitating the cellular redox homeostasis and promoting the tissue repair process. In conclusion, PBM with NIR 810 nm laser at pulsed-mode 10 Hz frequency showed better penetration and accelerated dermal wound healing in immunosuppressed rats.