Structural changes in the heart tissue of rats under conditions of acute intoxication with Vipera berus berus venom

Abstract

Among all poisonous animals, snakes attract the special attention of mankind. Cases of poisoning by their toxins are extremely common and are an unsolved public health problem worldwide. It has been established that among a number of complications due to snakebites, an important role is played by disturbances in the normal functioning of the organs of the cardiovascular system. The aim of the research is to study the features of histological changes in the heart tissue of rats under conditions of acute intoxication with Vipera berus berus venom. Experimental studies were carried out on white non-linear male rats. The animals were conditionally divided into two groups – a control and an experimental group of 10 individuals each. Experimental rats were injected intraperitoneally with a semi-lethal dose (LD50) (1.576 mg/g-1) of Vipera berus berus venom in saline solution. Animals of the control group were injected intraperitoneally with only saline solution. Rats were removed from the experiment 24 hours after exposure to the venom, anesthetized by cervical dislocation. Heart samples were taken for microscopic examination. Fixation of the material and preparation of paraffin blocks were carried out according to generally accepted methods. Histological heart preparations were stained with Picro Sirius Red/Fast Green. Histological preparations were studied using a SEO SСAN light microscope. Thus, under the conditions of acute intoxication with Vipera berus berus venom in experimental rats, microscopic examination of the heart tissue revealed pathological shifts in the structural organization of all layers of the organ. In the epicardium, an increase in the volume of collagen fibers and thickening of vessel walls were characteristic. The most pronounced histological changes were observed in the myocardium. Swelling, disorganization of muscle fibers, their fragmentation, lysis, destruction, loss of characteristic transverse striations, necrosis were detected in it. In addition, an increase in the number of fibroblasts, their activation and, as a result, the growth of connective tissue components, including collagen fibers, in the myocardial tissue were revealed. The endocardium of experimental rats was distinguished by desquamation of the endothelial lining and an increase in the number of active fibroblasts in the outer connective tissue layer.