Peculiarities of microscopic and histochemical changes in the structure of the liver of experimental rats under the influence of viper venom Vipera berus nikolskii

Abstract

Annotation. As a result of the significant distribution of poisonous animals, humanity is in constant contact with them, which often causes poisoning or fatal consequences. About 1.8-2.7 million cases of snake bites are registered every year, resulting in 81,000-138,000 deaths of the victims, and 100,000 of them are characterised by the development of irreversible physical or mental disorders. Their toxic substances show a wide range of pathological effects on most vital systems, causing damage to the lungs, heart, kidneys, and skeletal muscles. However, currently, the number of experimental works on the effect of the venom of various types of snakes and vipers on the morpho-functional changes of the liver is too limited. The study aims to study microscopic and histochemical changes in the liver of rats under the influence of viper venom Vipera berus nikolskii. Experimental studies were carried out on white, non-linear male rats. The animals were conditionally divided into control and experimental groups, ten individuals in each. Experimental rats were injected intraperitoneally with a semi-lethal dose (LD50) (1.576 mg·g-1) of Vipera berus nikolskii venom in a physiological solution. Animals of the control group were injected intraperitoneally only with a physiological solution. Rats were removed from the experiment 24 hours after exposure to the poison and anesthetised by cervical dislocation. Liver samples of animals of all groups were taken for microscopic examination. Histological preparations of the liver were stained with hematoxylin and eosin. Histological preparations were examined using an SEO SСAN light microscope. Histochemical studies were carried out using the Nakhlas method to identify the key enzyme of the citric acid cycle - succinate dehydrogenase. The sections were stained with Schiff's reagent after preliminary treatment with iodic acid (PAS reaction) in Shabadash's modification to study the features of glycogen accumulation in hepatocytes. The immunohistochemical method revealed a subpopulation of CD86+ cells in the liver of experimental animals. Under the conditions of exposure to Vipera berus nikolskii viper venom, the animals of the research group observed the development of pronounced destructive changes in the structural elements of the liver and links of the vascular bed, which is confirmed in particular by the reliable dynamics of changes in morphometric indicators. Dilation and filling of blood vessels, formation of blood clots, haemorrhages, and destruction of hemocapillary walls were determined. Macrophage activation was combined with leukocyte infiltration in the triad zones and locally in the periportal areas of the liver lobules. Violation of the lobular-beam structure of the organ was accompanied by hydropic dystrophy of hepatocytes, and a significant decrease in the content of succinate dehydrogenase and glycogen was also established.