Quantitative and qualitative evaluation of recovery process of a 1064 nm laser on laser-induced skin injury: In vivo experimental research

Laser biological effects are a hot topic in laser medicine. In this study, to explore the quantitative biological effect of laser-induced wound healing and to provide guidance for expanding the clinical application of laser therapy, the injury effects and repair characteristics of skin tissue are studied through infrared laser irradiation of the skin of miniature pigs. Live pig skin was irradiated at multiple spots one time by using a grid-array method with a 1064 nm laser at different power outputs. The skin injury reaction was observed immediately after laser irradiation from low to high doses. The incidence of skin injury was calculated quantitatively. The healing and pathological changes after laser-induced skin injury were observed dynamically within 6 h and for 28 d after laser irradiation. With the increase of irradiation dose, laser-induced skin injuries ranging from mild to severe appeared in turn. The damage threshold of laser irradiation ED₅₀ is 47.4 J cm^-2 with the laser; from 3 d to 28 d after irradiation, the pathological results showed that wound healing tended to be different in all groups, but this trend weakened with the increase in laser irradiation intensity. With the increased irradiation dose, skin injury appears as different types of injury plaques, ranging from mild to severe. Skin injury is worsened and the tissue repair trend is weakened with the increase in laser irradiation dose, producing a good dose-effect and time-effect relationship.