Fig. 4

Cytochrome c oxidase subunit II (COXII) overexpression attenuates the proapoptotic effect of TRAP1_shRNA on hypoxic cardiomyocytes. a Representative images of cardiomyocyte apoptosis were detected by TUNEL staining after transfection with TRAP1_shRNA, Ad_ COXII, or both, with or without hypoxia. Scale bar = 50µm. b Apoptotic rates of cardiomyocytes were quantitatively analyzed in each treatment group. c, d Western blotting (c) and quantitative analysis (d) were performed to detect cytochrome c (Cyt c) levels in the cytosol. GAPDH served as an internal control. e Caspase-3 activity in the cardiomyocytes was determined using the caspase-3 Colorimetric Assay Kit in each treatment group. *p < 0.05 vs normoxia group; **p < 0.05 vs hypoxia group and hypoxia+Cont_shRNA group, respectively; #p < 0.05 vs hypoxia+TRAP1_shRNA group and hypoxia+TRAP1_shRNA+Ad_GFP group, respectively. Data are presented as mean ± SEM. Error bars indicate SEM, p value was analyzed using post hoc Tukey’s tests. The experiment was repeated three times. Ad_COXII adenoviral vector encoding COXII, Ad_GFP adenoviral vector encoding green fluorescent protein, TRAP1_shRNA adenoviral shRNA specifically targeting TRAP1, Cont_shRNA adenoviral-mediated expression of scrambled shRNA, GAPDH glyceraldehyde-3-phosphate dehydrogenase, TUNEL terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling