[Regeneration and DNA synthesis in cultures of rat heart ventricles after damage to the cellular layer].

By means of the 3H-thymidine radioautography method replicative activity of myocytes and other cells in a dense layer of cellular culture of the traumatized ventricular myocardium has been studied in newborn (2-3-day-old) rats after lesion of the myocardium. Proliferation of the non-muscular cells is sharply suppressed after the cellular layer formation: their labelling index (LI) is 5.7 +/- 2.2% on the 8th day. Simultaneously, LI of unicellular myocytes is 25 +/- 6%, and that of binuclear ones, specific for the myocardium of mature animals is 6.4 +/- 2.9%. That demonstrates autonomy of DNA synthesis in myocytes from its suppression in the surrounding non-muscular cells. For 1-2 days after trauma intensive migration of fibroblasts into the wound is observed; they are often oriented perpendicularly to the edges of the cellular layer. There is an activation of DNA synthesis in the non-muscular cells in the wound area (in 20 h after the lesion LI is 73.4 +/- 1.7%) and in the layer edge directed to the wound LI is 23.9 +/- 0.0%, while in the depth of the zone situating close to the wound their LI is 7.8 +/- 2.4%. The replicative activity of mononuclear cardiomyocytes in the zone mentioned increases very weakly (LI 32 +/- 5%), and LI of binuclear ones is practically unchanged (6.1 +/- 2.3%). Karyo-kinetic activity is estimated by amount of binuclear cardiomyocytes and in the zone near the wound, in comparison to that in an intact layer, it does not change (35 +/- 3% and 34.4 +/- 2.5%).(ABSTRACT TRUNCATED AT 250 WORDS)