The Efficacy of Gallium-Aluminum-Arsenide Laser on Skin Wound Healing in Guinea Pigs

Background: Skin wounds have serious human consequences including pain, lost work days and marked reduction in quality of life. Many studies were conducted to seek new therapeutic methods for resolving or minimizing failures of tissue repair including therapeutic ultrasound, electrical stimulation and low power laser light. The laser technique was used in the treatment of wounded tissue by inducing vascular dilatation, collagen synthesis and by increasing tissue oxygenation. The suitable energy density of laser is still of debate. Aim of the Work: This study was conducted to evaluate the effect of gallium-aluminum-arsenide laser of different energy densities on the skin healing process. Material and Methods: This study was carried out on 45 adult guinea pigs. In each animal two fullthickness wounds (A & B) were induced with surface area of 200 mm2 each. Wound A was irradiated by GaAlAs laser daily at a wave length of 905 nm and wound B was used as a sham control. The animals were randomly divided into three equal groups (I, II & III) which were exposed to laser energy densities of 4, 30 & 60 J/cm2 respectively. Each group was subdivided into 3 equal subgroups (5 animals each) a, b & c and received laser daily for one, two & three weeks respectively. The wounds' surface areas (WSA) were measured. The animals were sacrificed one day after last laser application and pieces of unwounded skin as a control and skin fragments at the different wounds edges were collected. They were subjected to Hematoxylin & Eosin and Mallory Trichrome techniques and examined by light microscopy. Results: There was very highly significant decrease in WSA and enhancement of healing in laser-treated wounds compared to the sham control ones. Conclusion: Treatment with GaAlAs laser of different intensities was able to induce several modifications that accelerated the wound healing with best results obtained for energy density of 60 J/cm2