Effect of low intensity laser radiation on healing of open skin wounds in rats.

Two full thickness skin wounds were produced on either side of dorsal midline in rats to study the effect of low intensity laser radiation on wound healing. Wounds on left side were irradiated daily with Helium Neon laser at 4 Joules/sq cm for 5 min. Wounds on right side were not exposed and served as controls. The mean +/- SD of time required for complete closure in control group was 14.1 +/- 0.86 days (range 12-15 day) while irradiated test wounds took only 10.3 +/- 0.68 days (range 9-12 days) to heal (P < 0.001). Granulation tissue was significantly (P < 0.001) more in test than in control wounds. Early epithelisation with increased fibroblastic reaction, leukocytic infiltration and neo vascularisation was seen in the laser irradiated wounds. The collagen hydroxyproline concentration of scar tissue was also significantly higher (P < 0.001) in test group on 17th post-operative day. The study establishes the biostimulatory effects of low intensity laser radiation on healing of skin wounds.