Photoepilation: a potential threat to wound healing in a mouse.

Abstract

BACKGROUND: Theoretically, the bulge area which is known to be a reservoir of epidermal stem cells should be destroyed to achieve permanent photoepilation. We wished to determine whether wound healing capability is perturbed after photoepilation. METHODS: Twenty C57/BL6 mice were used. After wax epilation to synchronize the hair cycle, one-half of the backs of mice were photoepilated in the early anagen stage. After the two hair cycles of the mice to confirm the hair removal effect, 30% trichloroacetic acid was applied to the both halves of the backs of the mice. A skin biopsy was performed on both sides before and just after the injury, and 2, 6, 9, and 14 days thereafter. The specimens were evaluated histologically after staining with hematoxylin and eosin, Masson trichrome, and Verhoeff-van Gieson. RESULTS: No differences in wound healing times were evident upon gross observation by the naked eye. However, the photoepilated hairless skin was observed to have a thicker epidermis and dermis than normal hairy skin by histological evaluation. The cellularity of the healed wound was much denser in the photoepilated. Collagen production of the neodermis in the normal hairy skin was first observed around the lower part of hair follicle, while it started from the upper papillary dermis in photoepilated skin. CONCLUSION: Photoepilation may disturb the normal wound healing process, especially dermal wound healing, and increases the risk of producing hypertropic scar or keloid.