Analysis of superoxide levels in fetal heart at E12.5 using dihydroethidium (DHE) as a probe. (A) Representative images of DHE staining in the LV myocardium of fetal hearts. (B) Quantification of DHE fluorescence intensity. Data are means ± SEM, n = 5–6 samples per group. *P < 0.05 vs. untreated control, †P < 0.05 vs. untreated diabetes. Scale bar is 20 μm.