Fig. 2. Regulation of CT-1 and HIF-1 expression in embryoid bodies by endogenous ROS. Embryoid bodies were incubated from day 2 to day 8 of cell culture with 20 µM vitamin E. On day 8 protein expression of CT-1 and HIF-1 was assessed by semiquantitative immunohistochemistry in whole-mount embryoid bodies. The images show representative embryoid bodies labeled with antibodies either against CT-1 or HIF-1 which remained untreated (a,c) or were treated with vitamin E (b,d). ^*P<0.05, significantly different to levels in the untreated control.