Figure 1. Dox-treated cardiomyocytes exhibited increased cellular senescence. (A) Cell cycle analysis was performed with PI staining by flow cytometry. (B) Percentages of cells in the three phases of the cell cycle. (C) Cellular proliferation was measured using CCK-8 assay. (D) Representative images of SA-β-gal staining (senescent cells are stained green). Scale bars, 20 μm. (E) Percentage of senescent cells was calculated. (F) Representative p16INK4a staining (green). Scale bars, 20 μm. (G, H) Expression of miR-199a-3p in cardiomyocytes and cardiac tissue was quantified by qRT-PCR. *P < 0.05 versus control, n = 6 per group. (I) Representative photomicrographs of p16INK4a-positive cardiomyocytes in the Dox treated cardiac tissue. Scale bars, 100 μm.