Opa1 is downregulated in the infarcted heart and in hypoxia-treated cardiomyocytes. (A–D) Quantitative real-time PCR and western blot analysis of Opa1 expression. (E, F) Analysis of Opa1 expression in cardiomyocytes in vitro by immunofluorescence. (G) MTT assays of cardiomyocyte viability. (H, I) Analysis of cardiomyocyte apoptosis by PI staining. *P < 0.05 vs. the control group; #P < 0.05 vs. the hypoxia + ctrl-OE group.