Anthropogenic impact on the hydrosphere has acquired an alarming scale and causes a decline in the number of population of aquatic organisms. The vertebrate organism is a powerful factor in the accumulation of chemical elements in the hydrosphere. Fish often take on the burden of anthropogenic load, so conducting clinical trials is relevant. Histological analysis of the liver of fish showed adaptive organ responses, blood microcirculation disorders, and dystrophic changes in the parenchyma. Compensatory changes in the hepatocytes were morphologically indistinguishable from processes of adaptive cell rearrangement. The form of functional adaptation is dedifferentiation of cells both under normal conditions of tissue development and under the action of damaging factors. Microcirculation disorders are the first signs of pathological processes in the liver. In the conditions of prolonged exposure to toxicants, venous plethora, stasis was found. Fish liver is characterized by high reactivity and a large reserve of functional ability. In conditions of pathology, the functions of the organ are violated. Dystrophies are the most common morphological signs of these disorders. Dystrophic changes involve parenchymal structures. There often observed granular, hydrophilic and fatty degenerations of the hepatocytes in the pathology of the fish liver. Progression of granular dystrophy leads to the appearance of hydropic dystrophy. There were various vacuoles observed with fatty degeneration in the cytoplasm of the hepatocytes. Fatty vacuoles of cells are merge form of fatty cysts. The increased fat content in the fish liver is a consequence of the disturbance of metabolic processes during the action of toxicants. This can serve a diagnostic sign of the degree of organ damage in chronic exotoxicosis. In the case of a slow development of fatty degeneration, there is a moderate shift and an uneven squeezing of the hepatocytes. The nucleus is oriented centrally with rapidly developing fatty degeneration. The lipofanerosis is the most severe form of fatty degeneration. Functional deficiency of the parenchyma leads to the increase in the organ’s reticular tissue. The morphological picture of fibrosis is represented by an increase in the collagen fibers content. A variety of violations in the liver structure is one of the symptoms of body intoxication which precedes the development of cirrhosis. Changes serve a kind of biological indicator of the state of environment. The ecological situation in the water area of the Azov-Black Sea basin is generally unfavorable for the reproduction of species. Continuation of research is necessary to expand the understanding of the mechanism of toxicants' influence on carcinogenesis and improve the methodology of hygienic regulation of environmental factors.
Keywords: liver, parenchyma, pathology, toxicant
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