MORPHOFUNCTIONAL CHANGES OF THE MYOCARDIUM OF RATS AFTER THE EFFECT OF GENERAL AND LOCAL HYPOTHERMIA

Abstract

The aim of the study was to study changes in the myocardium under the action of general and local hypothermia at different levels of structural organization. The results of the research made it possible to reveal the general regularities of irreversible pathological changes in the heart wall after the effect of local hypothermia in dry cold, after the result of which there is pronounced damage to muscle fibers with their ruptures, and also to find out that after the effect of local hypothermia in a cardioplegic solution microscopically, the myocardium of the ventricles and interventricular membrane does not change. Our studies of the myocardium of the heart wall of rats using transmission electron microscopy showed that the use of this method allows us to assess the processes of remodeling the heart after hypothermia and confirm the completeness of the structure of the studied objects. The intercellular space between individual cardiomyocytes is increased. The oval nuclei in most cardiomyocytes are located mainly in the center of the cells, in some they are displaced to the periphery. The intercellular space between adjacent cardiomyocytes is larger than in the outer layer. On histological sections, hyperemic vessels, endothelium of small vessels and swollen capillaries were found. At the ultrastructural level, perevascular edema, edema of the mitochondrial cristae apparatus, erethrocytic sludge syndrome were revealed. In cardiomyocytes, swelling of the sarcoplasm is noted, especially in the zone of contact with the capillaries. There were few intermitochondrial contacts. Intermyofibrillar mitochondria were large, with moderately developed cristae and a transparent matrix. Among such organelles, organelles with elements of crystallization and zones of sharp enlightenment predominated. matrix. The revealed changes indicate the microcirculatory bed and the cell energy supply apparatus in aggregate indicate the activation of adaptive processes arising in cardiomyocytes under the influence of general hypothermia.

Keywords

• heart,myocardium,general hypothermia,local hypothermia,immunohistochemistry,ultrastructure,electron microscopy,electrophysiological study