HHcy-induced oxidative stress in SMAs of Tg-hCBS Cbs mice. Mouse SMA segments and cross-sections were incubated with the antioxidants PEG-SOD (150 U/mL) or the O2− scavenger Tempol (1mM), and stained with the O2− marker DHE (red, A) or 3-NT (green, C), and costained with endothelial marker CD31 (red, C) antibodies. Merged image (yellow to orange, C) shows that 3-NT is localized to the endothelium and increased in Cbs−/− mice. (B) Quantitative analysis of O2− generation by DHE staining in panel A. Values are means ± SEM (n = 5-7 mice). *P < .05 compared with vehicle in control mice; †P < .05 compared with vehicle in Cbs−/− mice. CT indicates the control group.