The effects of the helium neon laser on wound healing in rabbits and on human skin fibroblasts in vitro

Abstract

Helium-neon laser irradiation was applied to the denuded dermis and full-thickness open wounds on rabbit skin and cell cultures of human skin fibroblasts to investigate its effects on the wound healing process. To determine the effects of He-Ne laser radiation on epithelialization rate, 3×3 cm denuded dermis areas on the flank of 16 rabbits were irradiated daily until complete epithelialization occurred. For histopathological evaluation biopsies were taken on the first day and on the day on which epithelialization was complete. As a second part of in vivo study, identical full-thickness skin wounds were created bilaterally on the middle flank area of 12 rabbits. He-Ne laser irradiation was applied daily to the wounds until complete healing occurred to determine the effects of the low-energy laser on the contraction of open wounds. The contralateral wounds were left untreated, serving as controls. In a separate in vitro study, the effect of single or multiple applications of He-Ne laser irradiation on normal human skin fibroblasts in cell cultures was evaluated using growth measurement. The mean epithelialization time was 11±0.63 days for the laser-treated wounds and 12±0.12 days for the control wounds. The difference was not significant. No significant difference was found between the contraction rates of the full-thickness wounds (e.g., on the seventh postoperative day, the average wound area was 70.2±6.75% of original wound area in the laser-treated group and 66.±8.75% in the control group). Histopathologically, epidermal thickening and an increase in dermal vascularity were observed in healed wounds of the laser-treated groups. However, in vitro, this low-energy laser promoted cell growth in human fibroblast cell cultures in 2-and 3-day treated groups (p>0.05).