Photobiomodulatory effects of superpulsed 904 nm laser therapy on bioenergetics status in burn wound healing

Burn wounds exhibit impaired healing as the progression through the normal sequential stages of tissue repair gets hampered by epidermal barrier disruption, compromised blood circulation, abrogated defence mechanism, pathologic inflammation, and septicemia. Our earlier results reported that superpulsed 904 nm LLLT enhanced healing and attenuated inflammatory response in burn wounds. The present study investigated the effect of superpulsed 904 nm LLLT (200 ns pulse width; 100 Hz; 0.7 mW mean output power; 0.4 mW/cm2 average irradiance) on biochemical and molecular markers pertaining to bioenergetics and redox homeostasis on full-thickness burn wounds in experimental rats. Results indicated that superpulsed laser irradiation for 7 days post-wounding propelled the cellular milieu towards aerobic energy metabolism as evidenced by significantly enhanced activities of key energy regulatory enzymes viz. HK, PFK, CS and G6PD, whereas LDH showed reduced activity as compared to the non-irradiated controls. LLLT showed a significant increased CCO activity and ATP level. Moreover, LLLT also regulated redox homeostasis as evidenced by enhanced NADPH levels and decreased NADP/NADPH ratio. Western blot analysis demonstrated that LLLT produced an up-regulation of GLUT1, pAMPKα and down-regulation of glycogen synthase1 (GS1). Our findings suggest that superpulsed 904 nm LLLT augments burn wound healing by enhancing intracellular energy contents through modulation of aerobic metabolism for maximum energy output. Bioenergetic activation and maintenance of redox homeostasis could be one of the noteworthy mechanisms responsible for the beneficial NIR photobiomodulatory effect mediated through superpulsed 904 nm LLLT in burn wound healing.