The involvement of alpha-melanocyte-stimulating hormone in the hyperpigmentation of human skin autografts.

Abstract

Hyperpigmentation occurs frequently in human skin autografts, resulting in an unsatisfactory appearance. This study aims to elucidate the role of alpha-melanocyte-stimulating hormone (alpha-MSH) in the hyperpigmentation process of skin autografts by analysing the expression of alpha-MSH and the amount of melanin in human autografted skin and normal skin. Immunohistochemistry and reverse transcription-polymerase chain reaction methods were carried out to detect the expression and distribution of alpha-MSH and pro-opiomelanocortin (POMC) in skin autografts, including full-thickness skin autografts, split-thickness skin autografts and normal skin. The Fontana-Masson stain was used to detect the amount of melanin in all the skin specimens. The level of alpha-MSH and POMC expression in autografted skin was much higher than that of control normal skin, and thinner split-thickness skin autografts expressed higher levels of POMC mRNA and alpha-MSH protein. The amount of melanin in skin autografts was significantly higher compared with normal skin. The expression of alpha-MSH correlated well with the amount of melanin in skin autograft epidermis. These results indicate that the function of melanogenesis, transfer of melanin in melanocytes, was dramatically enhanced in skin autografts by alpha-MSH. The over-expression of alpha-MSH may play an important role in the hyperpigmentation process of skin autografts and provide a novel mechanism of this process.