Features of morphometric parameters of the myocardium after rats' exposure to the scorpion Leiurus macroctenus venom

Background. Toxic components of scorpion venom cause local symptoms and the development of severe neurological, hematological disorders, cardiovascular, respiratory, excretory systems, etc. Among the leading causes of death under these conditions are heart failure and pulmonary edema. Expanding the understanding of the effects of scorpion venoms will make it possible to establish pathogenetic mechanisms for developing certain complications and patterns of histological and biochemical changes in target organs. It can also be essential in developing treatment methods, prevention, and manufacturing medicines and antidotes. Objective. Morphometric analysis of changes in the structure of the rat heart wall and the course of hemodynamic processes in it in response to the effect of the venom of the scorpion Leiurus macroctenus. Methods. Experimental studies were conducted on 60 male rats (180 g±3 g), which were injected intramuscularly with 0.5 ml of the venom solution (28.8 mg/ml) (LD50=0.08 mg/kg). Morphometry of digital images was performed in the Fiji: ImageJ program. The width of cardiomyocytes and the percentage of myocardial area occupied by blood were determined. Results and conclusion. Against the background of the action of the scorpion venom Leiurus macroctenus, a statistically significant increase in the width of cardiomyocytes and the area of ​​hemorrhage zones in the myocardium is observed; these characteristics are more pronounced over time. Cardiomyocytes showed signs of pathological changes already in the first hour of the venom action, when, morphometrically, the difference from the control group was still impossible to register. In the case of cardiomyocyte sizes, if in the first hour after the venom administration, the increase in their width was not observed in the experimental group. The width was already significantly more significant in the third hour than in the control group. The area of ​​the vessels increased due to the aggregation in their lumens and near the walls of formed blood elements, the perfusion of the vessels themselves and edema of the middle and outer membranes. The area of ​​hemorrhagic zones outside the vessels was determined by the increase in permeability, or even the destruction of their walls, which led to diapedesis and passive penetration of formed blood elements into the surrounding tissues.