Abstract: Objectives To study the effect of supplemented four agents decoction formula (a decoction of Chinese medicines) on cell proliferation, cell toxicity and the expression of tyrosinase (Tyr) gene and c-kit (stem cell factor's ligand/receptor) protein in melanocytes isoloated from Caucasians.Methods The expression of Tyr and c-kit protein was detected by Western blotting.The whole protein of melanocytes was measured by its absorption at 595 nm against the standard concentration curve.The toxicity and cell proliferation were observed by cell count and microscopy.Results The whole soluble protein content and Tyr expression in cultured melanocytes were slightly increased 4.76% and 1.79% respectively after supplemented four agents decoction formula stimulation, as compared with those in the controls (P>0.05).However, this medicine significantly enhanced c-kit expression in melanocytes in vitro with an increase of 79.41%.Conclusions The efficacy of supplemented four agents decoction formula in the treatment of vitiligo may be related to the SCF (stem cell factor)/c-kit pathway.This Chinese traditional medicine may enhance c-kit expression, but may not be associated with cell proliferation and Tyr expression of melanocytes.

Key words: Melanocytes, Supplemented four agents decoction formula, Vitiligo, Monophenol monooxygenase, Receptor protein-tyrosine kinases