Involvement of melanocortin‐1 receptor in the hyperpigmentation of human skin autografts

Abstract

Hyperpigmentation frequently occurs in human skin autografts resulting in an unsatisfactory appearance. This study aimed to elucidate the role of melanocortin-1 receptor in the hyperpigmentation process of skin autografts by analyzing the expression of melanocortin-1 receptor. The data were correlated with the amount of melanin in autografted human skin and normal skin determined in a previous study. Immunohistochemistry, western blotting and quantitative real-time polymerase chain reaction were carried out to detect the expression and distribution of melanocortin-1 receptor in skin autografts including full-thickness skin autografts, split-thickness skin autografts and normal full-thickness skin. Fontana-Masson stain was used to detect melanin in all types of skin specimens. The expression level of melanocortin-1 receptor in autografted skin was much higher than that in control normal skin, and thinner split-thickness skin autografts had higher levels of expression of melanocortin-1 receptor than thicker grafts. The amount of melanin in skin autografts was significantly increased compared with normal skin. The expression of melanocortin-1 receptor correlated well with the amount of melanin in the epidermis of skin autografts. These results indicate that melanogenesis is dramatically enhanced in skin autografts by the melanocortin-1 receptor, and suggest that overexpression of melanocortin-1 receptor may play an important role in the hyperpigmented process of skin autografts. This study provides a novel mechanism for hyperpigmentation in skin autografts.