Effect of endothelial nitric oxide synthase on epidermal permeability barrier recovery after disruption

Background We previously demonstrated that neuronal nitric oxide synthase (nNOS) in epidermal keratinocytes is associated with epidermal permeability barrier homeostasis. Objectives In the present study, we examined the contributions of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) to epidermal permeability barrier homeostasis. Methods We measured the barrier recovery rate after tape stripping of the epidermis of iNOS and eNOS knockout mice, and carried out electron-microscopic observation of the epidermis after acetone treatment. Results The barrier recovery rate of eNOS knockout mice was significantly faster than that of the wild-type control, while no significant difference was observed between iNOS knockout mice and wild-type mice. Electron-microscopic observation at 1 h after acetone treatment indicated that barrier recovery of both nNOS and eNOS mice was faster than that of wild-type mice, and lamellar body secretion was accelerated in both types of knockout mice. Conclusions These results suggested that both nNOS and eNOS play roles in epidermal barrier homeostasis and lamellar body secretion.