Objective:To study the time- and concentration-dependent effect of DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine(5-aza-dC) and histone deacetylase inhibitor trichostatin A(TSA) on the expression of H19 gene in nuclear donor cells.Methods: Donor cells (fibroblast-like cells from tail tip of mice) were treated with 5-aza-dC and TSA at different concentrations for different time periods.The expression of H19 was determined by real-time PCR after treatment.Results: The expression of H19 was not significantly different between groups treated with different concentrations of 5-aza-dC,but the expression of H19 was increased with the increase of treatment time.TSA decreased H19 expression,but not in a time-dependent manner.Conclusion: Long time exposure to low concentration of 5-aza-dC can increase the expression of H19; TSA can decrease the expression of H19,which provides a basis for selection of epigenetic modification inhibitor and later study on imprinting in somatic cell nuclear transfer.