Bulletin of Medical and Biological Research

Summary. Today in Ukraine and in the world the study of the stress problem has become especially acute. Firstly, it is connected with sedentary lifestyle during the COVID-19 pandemic, and secondly, in connection with the war in Ukraine, in which the whole world is involved. Both causes contribute to the development of stress, which will lead to further diseases of various organs and systems. The aim of the study – to evaluate the development of oxidative stress in the blood of male rats with different motor activity under stress. Materials and Methods. The experiments performed on Wistar male-rats of 150– 170 grams, aged 3.5 months. Selection of animals for motor activity carried out using the method of "white open field". The number of horizontally intersected squares and vertical posts taken into account. At high level indicators were referred to were the group of highly active animals, at low – low-active. Chronic stress in rats was from 1.5 to 3 months of age, the animals kept in cages with limited living space twice. Slaughter of rats was performed under thiopental-sodium  anesthesia, blood was taken, where the diene conjugates (DC), TBA-active products (TBA-ap), oxidatively modified proteins (OMP), superoxide dismutase (SOD) and catalase activity where determined. All animals underwent histological examination of the heart at the level of both ventricles in Heidenhain-stained preparations. Apoptosis was predominant in animals with high motor activity in both control rats and stressed animals. The number of cells that underwent apoptosis was significantly higher in highly active animals. Results. Products of lipid peroxidation and OMP, SOD and catalase activity were dominated in the group of control animals in highly active males, compared with low-activity. In stressed rats, the DC, TBA-ap, OMP increased, and were more in highly active rats. Antioxidant activity increased in stressed animals. SOD and catalase activity were higher in low-activity rats The obtained data indicate the development of oxidative stress. Conclusion. The development of stress depends on the motor activitys. Stress causes an increase of proteins and lipid peroxidation in rats, which is more in high motor activity. The activity of antioxidants, more in low-activity individuals increased compensatory in the blood

lipid and protein peroxidation, antioxidant system, stress, motor activity