NEONATAL RAT MYOCARDIUM SURVIVAL IN TERMS OF CHRONIC HEMIC HYPOXIA

Аннотация

Hypoxia problem and its consequences are still relevant problems in perinatal medicine. The aim of the research was to investigate the neonatal rat’s myocardium structural adaptation in terms of chronic hemic hypoxia. In the experiment there were involved 15 female three-months old Wistar rats which were daily administered sodium nitrite solution at a dose of 50 mg/1 kg body weight throughout the pregnancy and for three days after giving birth to pups. Myocardium was taken from the pups that were fed the by above females and reached 3 days of age. Preparation of material for electron microscopy studies was conducted according to the standard methods. Additionally we applied La20H3 solution (lanthanum hydroxide) to determine the permeability of cell membranes. Content of malondialdehyde (MDA) was detected by the method suggested by M. Mihara. Cytochemical research included identification of the succinate dehydrogenase enzyme (SDH) by Nartsissov quantitative method. It was found out that changes in the ultrastructural organization of cardiomyocytes and endothelial cells of capillaries in the myocardium of newborn rats with chronic hemic hypoxia are accompanied by a very vivid mitochondrial dysfunction. It is structurally expressed by the outer mitochondrial membrane damage and lysis of crists confirmed by increased levels of MDA in serum and decreased activity of SDH in lymphocytes. The most pronounced damage occurs in the mitochondrial membranes accompanied by destructive structural vascular changes and focal lysis of myofibrils. Thus, hemic hypoxia of mother has a strong toxic effect on the myocardium of the neonates.