(a–d) In comparison to the vehicle control, increased levels of anti-apoptotic proteins, Bcl-2 and Bcl-xL, were noted in cytotrophoblastic cells treated with vitamins C and E at standard culture conditions. There was no difference in the levels of mitochondrial pro-apoptotic proteins, Bax and Bak, between the two groups. (e-h) In contrast, a decrease in the levels of Bcl-2 and Bcl-xL and an increase in the mitochondrial Bak protein levels were noted in cytotrophoblastic cells treated with vitamins C and E at HR in comparison to the vehicle control. Lane 1, vehicle control and lane 2, vitamin treatment group. Data are presented as mean ± SEM for 12 separate experiments. *, P<0.05; **, P<0.01 and ***, P<0.001, in comparison to vehicle controls.