[Morphology of adaptive-compensatory processes in the myocardium as affected by contrasting temperatures].

A comparative morphologic study of Wistar rat myocardium under contrast temperature influences (extreme and moderate general cooling and general overheating) was carried out. It is shown that different regimens of general cooling and general overheating cause dramatic structural changes in the myocardium both at the tissue and subcellular levels. Tissue changes manifested as hemodynamic disorders, contracture and lytic injuries to cardiomyocytes resultant in necrobiosis and atrophy of some cardiomyocytes. These changes were more pronounced under acute influences. Tissue spatial myocardium reorganization had a stereotype pattern. Quantitative changes of main parenchymatous and stromal structure did not differ significantly under various temperature regimens. At subcellular level more pronounced quantitative and qualitative changes of organelles were revealed under general cooling irrespectively of the duration of the experimental exposure.