Objective To study the effect of angiotensinⅡ（AngⅡ） on apoptosis in endothelial cells（EC）.  Methods Human umbilical endothelial cells were cultured in vitro and treated with AngⅡ in various concentrations alone and in combination with fumonisin B1(FB1

an inhibitor of ceramidase). TUNEL was employed to determine the apoptosis of the cultured EC. The bax mRNA and protein levels of EC were detected by RT-PCR and Westernblot techniques.  Results The results showed that the number of apoptotic cells

was significantly higher in AngⅡ-treated endothelium than in the control group（P0.05）. AngⅡ induced EC apoptosis in time- and dose-dependant manner. The percentage of the apoptotic EC were (2.2±1.1)%

(6.0±1.2)%

(17.5±2.3)%

(27.4±4.5)% respectively after treatment with AngⅡ at various concentrations（0

10

-7

10

-6

10

-5

mol/L）for 24 h. Exposing to 10

-6

mol/L AngII for 6

12 and 24 h

the rate of apoptotic cells were (6.2±2.3)%

(15.5±3.1)%

and (21.6±2.5)% respectively. Compared to AngⅡ group

FB1 inhibited EC apoptosis induced by AngⅡ(P0.05).The expression of bax mRNA and protein in EC treated with AngⅡ significantly increased（P0.05）but not significant with the FB1 group（P0.05）.  Conclusion AngⅡ may induce apoptosis of endothelial cells via ceramide and up-regulating the bax mRNA and protein expression. Ceramide is the upper stream of bax and induces apoptosis by bax pathway.