THE MORPHOLOGY OF THE ACCIDENTAL INVOLUTION OF THE THYMUS AT THE EXPERIMENTAL CANCEROGENESIS

Abstract

The development of tumors in the body is a powerful factor in the dysfunction of the immune system. The features of involution processes in the thymus in experimental carcinogenesis are due to impaired metabolism in the body as a whole and the production of lymphoid cells with altered functions. The purpose of the study is to summarize data from modern scientific literature and own research on the accidental transformation of the thymus and the reaction of its cellular structures against the background of experimental carcinogenesis with the development of a mammary gland tumor, stress and the combined effect of these factors. Based on the analysis, it was found that dendritic and mast cells of the thymus respond most actively to tumor growth and stress. Morphometric parameters and changes in organ's cytoarchitecture correspond to the phases of the development of accidental involution, which is most pronounced with the combined effect of two factors. A significant role in these processes belongs to biogenic amines and hormones. The introduction of carcinogens leads to a structural reorganization of the gland: the lobules become more elongated, the interlobular spaces increase, the thickness of the cortical and the area of the medulla increase. There is a decrease in the number of S-100+-cells, an increase in the number of mast cells with a predominance of degranulated and completely devastated forms. The level of histamine in the cells of the pre-medullar area decreases in 1,3 times, in the thymocytes of the cortex and medulla in 1,7 times. Along with the change in the level of biogenic amines, there is a decrease in the ratio of their ratio, which indicates an increase in the functional activity of cells. Against the background of stress, as an additional factor that depresses the immune system, there is a pronounced disorganization of the thymus lobes: a decrease in the thickness of the cortical and the area of the medulla, expansion and filling of the interlobular connective tissue septa with adipose tissue. The number of dendritic cells also decreases and the content of degranulated and completely devastated forms of mast cells increases, the level of histamine significantly decreases in all structures. Thus, data from the literature and our own research indicate that the combined effect of carcinogenesis and stress leads to more pronounced changes in the structure of the thymus in the process of accidental involution and the structural specificity of its manifestations.