Microstructure of thymus of white rats during the chronic study of UMVK "Lizunets Solevit"
Due to the imbalance in the diet of animals by macro- and micronutrients, violations of feeding and maintenance technology lead to metabolic disorders, and also leads to suppression of the cellular and humoral factors of the immune response, which leads to a decrease in the natural resistance of animals. The aim of the work was to study the effect of the Lizunets Solevit UVMK in chronic use with white rats. For this reason, outbred white rats of both sexes were selected, divided into 4 groups of 12 animals each, with an initial weight of 50-60 g. The drug was administered orally as an aqueous suspension for 30 days, the first group at a dose of 1/10, the second group 1/20, the third group 1/50 of the LD<sub>50</sub> and the fourth group served as a control, which was given distilled water. After administration of the drug, animals were monitored: the clinical picture, behavioral reactions were evaluated, and the recovery time of functions was established. On day 31, experimental animals were sacrificed, a thymus was taken, and after fixation in a formalin solution, they were sent to a laboratory for the manufacture of histo sections and subsequent processing. According to the results of a morphological study, as indicators of the histogenetic activity of the thymus of white rats at different doses of the Lizunets Solevit UVMK during the study, they differed from the control group of rats with the difference in lymphoid tissue of perishing forms of lymphocytes and very few epithelial reticulocytes, markedly swelling of the cortical substance. Changes were observed that when using the drug in the maximum dose, it slows down the age-related involution of the thymus of white rats.