The thesis is devoted to the study of the morphofunctional features of the thymus and spleen of laboratory WAG population male rats in normal conditions and changes at all levels of their organization due to the exposure to xenobiotics of the polyesters group 1/10LD50 and 1/100LD50 doses in subacute experiment. Animals were treated via gastric gavage with tryglycidyl ether of polyoxypropylene triol and propylene glycol-1,2 and withdrawn from the experiment on 7th, 15th, 30th, 45th day. The individual variability oscillations of the rats' thymus and spleen morphometric parameters in norm (min - max): mass, volume, width, length, height, and under the influence of tryglycidyl ether of polyoxypropylene triol and propylene glycol in doses 1/10LD50 and 1/100LD50 are established. Individual variations of the thymus are determined using the Index of height/length, Index of height/width, Index of thymus (width/length). Individual variations of the spleen are determined with the help of the Index of height/length, Index of height/width, Index of spleen (width/length). A comparative analysis of the different doses effect of tryglycidyl ether of polyoxypropylene triol on the morphometric indices of the thymus and spleen was carried out, the maximum changes in the mass of organs noted on the 7th day, their length and width on the 30th day, and height - the same effect throughout the experiment were established. According to a comparative analysis of the effect of propylene glycol between doses on the morphometric parameters of the thymus and spleen, the same effect was determined during the experiment (p<=0.05). Morphological changes in the thymus and spleen under the influence of xenobiotics depend on the experiment duration, the dose used, and the xenobiotic type. The most pronounced changes in organs were established with the use of tryglycidyl ether of polyoxypropylene triol 1/10LD50 on 45th day and characterized by a decrease in the density of cellular elements in the cortical zone of the thymus by 28.76 %, in the medulla - by 28.23 %, in the spleen by 27.70 % in the mantle zone and 24.09 % in the marginal zone. Established that white pulp, diameter of the lymph nodes, width of the mantle and marginal zones gradually decrease with the course of the experiment, indicating the hypoplasia of the spleen. The width of the periarterial zone increases due to the development of sclerotic changes, including thickening of the vessels walls. Ultramicroscopic organs' features under the influence of various xenobiotics doses were revealed. The activity of demylated enzyme MGMT in the thymus and spleen is characterized by early activation on 7th day and a gradual decrease in the next period, that is proved by statistically reliable data in rodents withdrawn from the experiment on 45th day. With the administration of 1/10LD50 tryglycidyl ether of polyoxypropylene triol on 45th day, the MGMT activity decreased by 33.94 %, due to influence of 1/10LD50 propylene glycol by 22.62 %. The obtained results are explained by the influence of xenobiotics on the processes of alkylation, which leads to cell death through apoptosis.
