Microscopic organisation of the myocardium of experimental rats 1 and 3 hours after exposure to the venom of the scorpion Leiurus macroctenus

Background. Animal venom toxins are characterised by significant variability in structure and biological effects. They are usually represented by proteins, numerous peptides that have undergone restructuring over many years of evolution, which influenced the mechanisms and features of their effect on the victim's body. Scorpion venom can cause myocardial damage, initiating many pathogenetic mechanisms. After bites from these animals, the development of myocardial infarction due to coronary spasms is quite often recorded. Objective. Study of microscopic changes in the heart of mature rats 1 and 3 hours after exposure to 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 venom solution (28.8 mg/ml) (LD50=0.08 mg/kg). Heart samples of animals from all groups were taken for microscopic examination. Histological preparations of the heart were stained with hematoxylin and eosin, azan trichrome and iron hematoxylin. Results and conclusion. Administration of Leiurus macroctenus scorpion venom to rats resulted in the smoothing and homogenisation of cardiac muscle fibres and their moderate hypertrophy. Diapedetic haemorrhages and pronounced lymphohistiocytic infiltration were observed. After 3 hours of the experiment, the deepening of morphological changes in the rat myocardium was detected. Wave-like deformation of muscle fibres and their pronounced oedema was noted. Edematous changes, lymphocytic infiltration, and haemorrhages characterised the stroma of the cardiac muscle. Manifestations of desquamation of the endothelial lining of the vascular wall and perivascular lymphohistiocytic infiltration were observed.