МОРФОЛОГИЧЕСКИЕ ИЗМЕНЕНИЯ СОСУДИСТОЙ СИСТЕМЫ ПЕЧЕНИ КРЫС ПОД ВОЗДЕЙСТВИЕМ ТИОАЦЕТАМИДА

Abstract

Background. Angiogenesis plays a key role in the progression of liver fibrosis. However, the available data on morphological changes in the liver vascular system are insufficient and contradictory. Objective. The aim of the work is to study the morphological changes in the liver vascular system of rats under the influence of thioacetamide. Material and methods. Fibrosis and cirrhosis of the liver in Wistar rats were induced with thioacetamide given at a dose of 200 mg/kg of animal weight for 17 weeks. To study morphological changes, we used classical and immunohistochemical staining methods. Microscopic analysis was performed using OLYMPUS BX51 microscope and image analysis software ImageScope Color and cellSens Standard. Results. The introduction of a solution of thioacetamide through the stomach leads to a gradual increase in the progression of pathological changes. In addition, it permits to track all stages of cirrhosis development and morphological restructuring of the liver vascular system. Throughout the experiment there was intensive capillarization of the parenchyma sinusoids and neoangiogenesis in the portal tracts and connective tissue septa manifested by the formation of many venules and small veins. We also observed an increase in the area of interlobular veins, which in some places had reached gigantic proportions. Three morphological phenotypes of CD34-positive cells were revealed. In the interlobular arteries as well as interlobular, central and sublobular veins, these cells had an elongated shape and a rod-shaped dark-colored nucleus. During the transformation of liver fibrosis into cirrhosis CD34-positive cells of an elongated shape with light roundedelongated nuclei were observed in the sinusoids closer to the periphery of individual false nodules. Rounded cells with dark-colored nuclei were present in the connective tissue near the hepatic triads, in the connective tissue septa among the cells of the infiltrate and between the sharply increased number of bile ducts. Conclusions. The established complex phenotypic changes in sinusoidal endothelial cells prove a close connection between fibrogenesis and neoangiogenesis. They probably play a leading role in the development of fibrosis and restructuring of the venous system of the portal vein.