Cardiomyocyte proliferation in rat fetuses under normal conditions and after heart injury.

Heart injury was inflicted to outbred albino rat fetuses on day 16 of prenatal development and cardiomyocyte proliferation was evaluated in the left ventricular zones adjacent to the wound and distant from it. The mitotic index of experimental animals was higher than in intact controls only for zones distant from the injury on day 10 after the intervention. The percentage of pathological metaphases gradually increased in all experimental groups, which causes doubt in the viability of postmitotic cardiomyocytes.