AR and myocardial infarction: Cell-cycle activity was also significantly more common in cardiomyocytes from ARP1MIP28 hearts than from MIP28 hearts on P35 (G1S: p = 1.06 × 10−58; S: p = 9.67 × 10−12; G2M: p = 7.44 × 10−66; M: p = 4.11 × 10−7) but not on P42, which suggests that AR on P1 promoted cardiomyocyte proliferation for approximately 1 week after MI induction on P28.