Objective To observe the effect of dexamethasone on the proliferation and apoptosis of embryonic palatal mesenchymal（EPM） cells, and chose a proper concentration of dexamethasone which can effect the ordinary growth of embryonic palatal mesenchymal cells. Methods The primary EPM cells were isolated and cultured in vitro, then we did biological assay. EPM cells were treated with different concentration dexamethasone（1×10-9, 1×10-8, 1×10-7 and 1×10-6 mol·L-1） respectively. The proliferation of EPM cells was evaluated using MTT method. Apoptosis was examined quantitatively with fluorescein stain. Results In the condition of blood serum’s concentration at 10%, optical density step down following the raise of dexamethasone’s concentration. The effect of dexamethasone got to a summit at 3 days. Inhibition rate of dexamethasone at 1×10－6 mol·L-1 was the highest. Conclusion Dexamethasone at 1×10－6 mol·L-1 can not only inhibit the growth of the EPM cells, but also will not lead to a large number of cells death. Therefore, this concentration can be used as a reference standard in future research. The most significant drug action time of dexamethason appears at the third day after administration, then the effect became weaken following the drug metabolism.
