[Dynamics of DNA concentration in the nuclei of rat cardiac muscle cells in experimental myocardial infarct].

The content of nuclear DNA was determined microspectrophotometrically in rat cardiac myocyte nuclei at various intervals after the onset of experimental myocardial infarction. In the intact rat heart 1.5 to 1.8% of myocyte nuclei contained tetraploid DNA. Myocardial infarction activated the process of polyploidization in the nuclei of the myocytes particularly in those surrounding the lesion. This process was most intensive during the first week. At later intervals there was an evidence of continuously increasing polyploidization.