MORPHOLOGICAL CHANGES OF THE HEPATIC PORTAL TRACTS IN EXPERIMENTALLY INDUCED CHOLESTASIS.

The dynamics of morphological changes developed in liver and bile ducts in biliary obstruction are well studied in the animal models of biliary obstruction, however,the data on the morphology of the portal tracts are scarce. The aim of the research was to study the structure of the portal tracts and interrelationship of their structural components in experimental biliary obstruction. The investigation was conducted on albino Wistar rats weighing 200-250 g, undergone biliary obstruction by common bile duct ligation (CBDL). The histological, histochemical and immunohistochemical investigation of the liver tissue stained with Hematoxylin& Eosin, Masson's trichrome and marked with CK8antibody were performed on the 3rd, 6th and 12th days after CBDL. The CBDL-induced biliary obstruction triggers a systemic reaction of the bile ducts and a complex of accompanying reactions that is heterogeneous, depending on the caliber of both the bile ducts themselves and the portal tracts containing them.CBDL causes dilation of the large bile ducts, their pressure on the portal veins with the deformation of their lumens, changes in the architectonics of the portal tracts, and expansion of the portal areas accompanied by increasing portal fibrosis and ductular reaction. The small bile ducts are less prone to dilation under CBDL conditions but actively proliferate and penetrate widely into the parenchyma of the liver lobules. Based on this ductal reaction, fibrosis of increasing intensity develops, which connects the adjacent portal tracts as well as the portal tracts and the connective tissue sheaths of the thin tributaries of hepatic veins. In the conditions of such fibrosis, it is difficult to identify the individual portal tracts of small caliber and, moreover, to clarify the relationship between their elements.

[; ADAPTATION OF THE BILE DUCTS OF THE PORTAL TRIAD IN CASE OF MECHANICAL CHOLESTASIS (REVIEW)].

In case of mechanical cholestasis, along with stagnation in the veins and bile ducts, lymph production increases, which contributes to the accumulation of ascitic fluid. In the peribiliaryareas, where the extramural biliary glands are located, an accumulation of lymphatic vessels has been observed in all the preparations.In these same areas, a contrast-enhanced microtomography showed transition of the ink-gelatin contrast agents (using gelatin and India ink) from the extramural part of the mucous glands to the lumen of the lymphatic capillaries and blood vessels.Lymphobiliary connections were visualized during the preparation of the sections of the portal triad of the lobar and sectoral portal tracts under a binocular microscope. More reliable evidence of the existence of lymphobiliary connections in the portal triad region was revealed on histological preparations stained with traditional methods.; Thus, anatomically, the area of the portal triad appears to be one of the alternative areas of lymphobiliary communications, which further confirms its high adaptive capacity in case of stagnation of bile.