Cardiomyocyte apoptosis in each group. A) Hypoxia-inducible factor-1α (HIF-1α) and mesenchymal stem cell (MSC) intramyocardial injection decreased cardiomyocytes apoptosis one week after infarction. Apoptosis nuclei stained by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) (red), total nuclei were labeled with 4, 6-diamino-2-phenylindole (DAPI) (blue). Cardiomyocytes were stained with anti-α-SA antibody (green). (I) HIF-1α + MSCs group, (II) HIF-1α group, (III) HIF-1α-MSCs group, (IV) MSCs group, (V) Control group, VI. SHAM. B) Apoptosis Index. ★P <0.05 vs. HIF-1α-MSCs group, △P <0.01 vs. MSCs group, * P <0.01 vs. Control group, ※P <0.01 vs. SHAM group, ▲P <0.05 vs. MSCs group, #P <0.05 vs. Control group.