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

Hyperpigmentation occurs frequently in human skin autografts, resulting in an unsatisfactory appearance. Objective: 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. Methods: Immunohistochemistry and reverse transcription-polymerase chain reaction methods were carried out to detect the expression and distribution of alpha-MSH and proopiomelanocortin (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. Results: 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. Conclusions: 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. (C) 2009 Elsevier Ltd and ISBI. All rights reserved.