Abstract: Objective To study the effects of tacrolimus on the cell proliferation of and secretion of stem cell factors（SCF） by cultured human keratinocytes. Methods Human keratinocyte cell line HaCaT was cultured and treated with various concentrations （0, 10, 102, 103, 104 nmol/L） of tacrolimus. After 48 hours of treatment, cell proliferation was measured with MTT assay , the levels of stem cell factor in the culture supernatant of HaCaT cells were detected with ELISA. Results Inhibited proliferation was observed in HaCaT cells treated with tacrolimus of 103-104 nmol/L. The secretion of SCF by HaCaT cells was enhanced in the presence of 10-102 nmol/L of tacrolimus, was inhibited in the presence of tacrolimus of 104 nmol/L, and remained unchanged with 103 nmol/L. Conclusion Certain concentrations of tacrolimus could enhance the expression of SCF in HaCaT cells, which may be associated with the efficacy of tacrolimus in the treatment of vitiligo.

Key words: FK506, Vitiligo, Melanocyte, Tacrolimus