Sebum's effect on wound healing and pigmentation in mice.

Background: Wound healing is often followed by postinflammatory hyperpigmentation (PIH), which commonly develops in sebum-poor areas. Objectives: To investigate the effects of sebum on wound healing, especially relative to basement membrane recovery and PIH. Methods: Using 100% trichloroacetic acid, we created deep dermal wounds on both sides of male HRM-2 hairless melanin-containing mice. The left side served as the control group, while the right side received daily sebum application for 21 days. The wound healing status and degree of pigmentation were evaluated by visual wound assessments and image analyses. Histological analysis and electron microscopy (EM) examinations were performed on days 7, 14 and 21, to compare basement membrane recovery and pigmentation. Results: The sebum group exhibited faster wound healing, including quicker crust removal and wound contraction, and reduced pigmentation, although this difference was not statistically significant. Histological and EM analyses seemed to show accelerated basement membrane recovery and delayed onset of melanosome accumulation with sebum treatment. We also performed cell viability and melanin contents assays using B16F10 melanoma cells, revealing that sebum decreased melanogenesis by inhibiting tyrosinase activity, without cytotoxicity. Conclusions: Overall, our results suggest that sebum might promote wound healing, with faster basement membrane recovery, and reduce PIH.