Objective To detect the treatment effect of PC3 cells with triptolide on altering the expression of genes.Methods MTT assay was used to detec the inhibition of proliferation.Apoptosis was detected by Annexin-V/PI staining.RT-PCR was used to analyze the mRNA expressions of BCL-2,BAX,PIG3,P21,FAS,CASPASE3.Results Triptolide caused a time - and dose - dependent inhibition of cell proliferation,and IC50 of 24 h and 48 h were 18.3 ng/ml and 13.5 ng/ml,respectively.Compared with the 24 h group,the low concentration of triptolide(5 ng/ml,t =1.47,P ＞0.05)and the high concentration of triptolide ( 160 ng/ml,t =0.91,P ＞0.05)had no statistical significance in 48 h group,while 10 ng/ml( t =3.26,P ＜0.05),20 ng/ml( t =4.21,P ＜0.05),40 ng/ml( t =4.09,P ＜0.05),80 ng/ml( t =2.91,P ＜ 0.05 )had statistical significance.At the concentration of 18.3 ng/ml,triptolide induced PC3 cells apoptosis in a time - dependent manner.Compared with the control group,Anexin-V( + )/PI(-)was(5.42±2.21)％(t =3.52,P ＜0.05)in 6h,(13.51±3.37)％(t =6.53,P ＜0.01) 12h,(29.3 ±4.53)％ ( t =8.74,P ＜0.01) 24 h group separately,and it had statistical significance.RTPCR showed that 18.3 ng/ml triptolide up-regulated the mRNA expression of BAX and PIG3,down-regulated P21 and BCL-2.FAS and CASPASE3 did not show obvious changes.Conclusions Triptolide inhibits the proliferation of PC3 and induces apoptosis,and the changes of BCL-2,BAX,PIG3 and P21 may play an important role in the apoptosis of PC-3 cells.