Effects of tert-butyl hydroperoxide (t-BHP) on apoptosis. TUNEL assay of rat aortic endothelial cells (ECs). TdT-mediated dUTP-biotin nick end represents TUNEL-positive (arrowhead), i.e. apoptotic cells. Blue color represents cell nuclei counterstained with DAPI. (A)
t-BHP-treated cultured ECs contained more positive cells (green color) compared with the controls (Cont). Scale bar indicated as 80 μm. (B) Quantitative analysis of TUNEL-positive to DAPI-stained cell ratio. Significantly higher levels were found in cells treated with t-BHP at concentration higher than 100 μM in comparison with the Cont. Data were from at least three independent experiments and represented as mean ± S.E.M. * p<0.05, ** p<0.01, and *** p<0.001, compared to Cont group. (C) Representative sections for TUNEL assay of rat aortic rings from t-BHP-treated groups. Scale bar indicated as 20 μm. (D) Quantitative results showed more positive TUNEL index, compared with the Cont at 6-week-old (the young group) and 24-week-old (the mature adult group). Data were from 4 rats in each group and from three independent experiments. * p<0.05, and ** p<0.01, compared to Cont group.