Histological features of the mitral valve in normal and opioid exposure in experiment

Abstract

To date, pathology of the cardiovascular system is the most common, tends to increase, most often leads to disability and mortality of the population at a young working age and is an important medical and social problem. The purpose of the study was to establish the features of micro organization of the mitral valve in white rat in norm and after opioid action. The study material is presented by histological samples of a mitral valve of the white rat. The study was performed on 30 adult white reproductive age rats weighing 160-220 g. The experimental animals were injected intramuscularly 1 time per day for the same period of 42 days (6 weeks) with the opioid drug analgesic “Nalbuphine”. Using histological methods, 30 mitral valves of white rat were examined. Microscopy of histological preparations of the valves of the heart was performed sequentially, assessing the morphological changes in the norm and under the action of the opioid after 6 weeks of the experiment. Emphasis was placed on the presence or absence of endothelial layer, as well as the condition of endothelial cells in normal and at the action of the damaging factor, determining the signs of their dystrophy, desquamation and proliferation. It is established that the normal mitral valve is represented by endocardial folds. The rat endocardium consists of three layers: endothelial (endothelial cells rich layer, attached to the basement membrane), subendothelial (connective tissue rich in fibroblasts) and a muscular-elastic layer (represented by smooth myocytes, plaited collagen fibers). After 6 weeks of administration of Nalbuphine, the mitral valve is in a stage of decompensation, when the outer and inner endothelial layers are destroyed, the endothelial cells are deformed, the subendothelial layer is represented by single bundles of different directions. In the musculo-elastic layer, contact between smooth myocytes and fragmented and thinned, collagen and elastic fibers is lost. This study allows us to conclude on the destructive effect of opioid agents on the valvular apparatus of the heart.