[Histostereologic analysis of the myocardium of homoiothermic animals during cooling]

A stereologic study of the myocardium exposure to cold for 4 hours, 8 and 16 days was carried out on Wistar rats. It has been shown that during the first 8 days acute hemodynamic disorders and cardiomyocyte contractures developed. These changes were followed by a decrease in the volume and surface capillary density resulting in the impairment of transcapillary exchange and reduction of the intracellular regeneration processes in cardiomyocytes. By the 16th day the compensatory-adaptive reactions developed, i.e., the volume and surface density of endothelial cells and capillaries was increased. At the same time the lysis processes caused by the general decrease in the inflow of plastic substances to the myocardium due to the increase in thermogenesis were revealed in part of cardiomyocytes. These changes in parenchymatous cells were accompanied by the intensification of desmoplastic reactions in the myocardial stroma.