Effects of neodymium-yttrium-aluminum garnet (Nd:YAG) pulsed high-intensity laser therapy on full thickness wound healing in an experimental animal model

OBJECTIVE: Wound healing can be aided by the use of low- and medium-intensity lasers. The use of pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) high-intensity laser therapy (HILT) with a 1064-nm wavelength laser provides deeper and more efficient penetration into tissue as it is being less absorbed by chromophores in tissue, e.g., hemoglobin, melanin, and water, thereby enhancing the wound-healing process. In this study, we examined the effect of HILT on wound healing with a Q-switched pulsed Nd:YAG laser in an animal model. DESIGN: Sixty SKH1 hairless male mice (seven weeks old) were randomly divided into four groups according to the amount of laser fluence: control, group 1 (0.8 J/cm2), group 2 (1.6 J/cm2), and group 3 (2.0 J/cm2). Laser treatment was provided to groups 1, 2, and 3 with a 1064-nm Q-switched Nd:YAG laser. Histological analysis was performed with hematoxylin and eosin staining, Masson's Trichrome staining, and Ki-67 staining. RESULTS: Statistically significant increases in the accumulation of collagen fibers, thickness of granulation tissue, and numbers of fibroblasts were observed in group 2 (treated with 1.6 J/cm2) as compared with the control (no laser treatment), group 1 (treated with 0.8 J/cm2), and group 3 (treated with 2.0 J/cm2). CONCLUSION: Nd:YAG HILT stimulated fibroblast proliferation and increased extracellular matrix production. We expect that this therapy could accelerate the wound-healing process.