Abstract: Objective To study the effects of 8-methoxypsoralen (8-MOP) on activation, proliferation and melanin synthesis of hair-follicle melanocytes. Methods The cultured human hair follicle melanocytes were treated with various concentrations of 8-MOP(10～500 ìmol/L) in vitro. The effects of 8-MOP were observed on cellular morphologic changes, proliferation, tyrosinase activity and melanin contents of cultured melanocytes. Results Sevendays after treatment with 8-MOP(50 ìmol/L), striking changes were found in cellular morphology with many elongated dendrites, and deposition of brown granules in cytoplasm. Tyrosinase activity and melanin contents also remarkably increased in treated cells compared to those in untreated cells(P<0.01). Conclusion 8-MOP can induce proliferation, tyrosinase activity and melanin synthesis of human hair follicle melanocytes.

Key words: Hair follicle, Melanocytes, Methoxypsoralen, Melanins