Photo-biomodulatory response of low-power laser irradiation on burn tissue repair in mice.

The present work reports the photo-biomodulatory effect of red (632.8 nm) and near infrared (785 and 830 nm) lasers on burn injury in Swiss albino mice. Animals were induced with a 15-mm full thickness burn injury and irradiated with various fluences (1, 2, 3, 4, and 6 J/cm(2)) of each laser wavelength under study having a constant fluence rate (8.49 mW/cm(2)). The size of the injury following treatment was monitored by capturing the wound images at regular time intervals until complete healing. Morphometric assessment indicated that the group treated with 3-J/cm(2) fluence of 830 nm had a profound effect on healing as compared to untreated controls and various fluences of other wavelengths under study. Histopathological assessment of wound repair on treatment with an optimum fluence (3 J/cm(2)) of 830 nm performed on days 2, 6, 12, and 18 post-wounding resulted in enhanced wound repair with migration of fibroblasts, deposition of collagen, and neovascularization as compared to untreated controls. The findings of the present study have clearly demonstrated that a single exposure of 3-J/cm(2) fluence at 830-nm enhanced burn wound healing progression in mice, which is equivalent to 5 % povidone iodine treatment (reference standard), applied on a daily basis till complete healing.