Figure 2. Role of Hif‐1α (hypoxia‐inducible factor 1‐α) in upregulating p53 expression and apoptosis induced by PHD (prolyl hydroxylase domain) inhibition using CoCl₂ in cultured rat cardiomyocytes.

A, Tp53 expression in cultured cardiomyocytes treated with vehicle (Veh) and CoCl₂ (500 μmol/L) for 24 hours, or transfected with small interfering RNA (siRNA) for control (CTL) (scramble siRNA, CTL) and Hif‐1α, was quantified by quantitative reverse transcription‐polymerase chain reaction; n=6 in each group. B, Western blots of Hif‐1α, p53, and CC‐3 (cleaved caspase‐3) in cardiomyocytes treated with Veh and CoCl₂ (500 μmol/L) for 24 hours, or transfected with siRNA for CTL (scramble siRNA, CTL) and Hif‐1α. GAPDH (glyceraldehyde‐3‐phosphate dehydrogenase) was used as a loading CTL. C, Quantification of Western blots shown in (B); n=6 in each group. Data are shown as a ratio to the average of Veh+CTL. D, Representative images of cardiomyocytes treated with Veh and CoCl₂ (500 μmol/L), or transfected with siRNA for CTL (scramble siRNA, CTL) and Hif‐1α. E, Cellular viability using cultured cardiomyocytes treated with Veh and CoCl₂ (500 μmol/L), or transfected with siRNA for CTL (scramble siRNA, CTL) and Hif‐1α by CellTiterBlue Assay; n=5‒6 in each group. **P<0.01, analyzed by 1‐way ANOVA, followed by Tukey post hoc test. KD indicates knockdown; and N/A, not applicable.