[Reparative processes during embryonal and postembryonal myocardiogenesis in Gallus domesticus L]

By means of light and electron microscopy methods during embryonal and postembryonal periods in birds (Gallus domesticus L.) myocardial reparative processes have been studied after its lesions produced with electrothermocoagulation. Primary closing of the wound in the cardiac wall of 3- and 5-day-old chick embryos is connected with certain reactive changes in epicardium and endocardium. In 7-10 days the cardiac wall completely restores its integrity by an intensive growth and development of intact cardiac areas. A weak development of the myocardial connective tissue stroma contributes to it. Reparative processes in the cardiac wall of 18-day-old chick embryos and in newly hatched chickens proceed with an active participation of the connective tissue, which subsequently forms a scar at the place of the lesion. Isolated redifferentiating cardiomyocytes surrounded with the connective tissue are subjected to atrophy on the 45th-60th day.