Qualitative and quantitative analysis of histological changes in cardiomyocytes of rat embryos during days 18-20 under conditions of alcohol intoxication in the maternal organism

Background. Alcohol is a teratogen that can easily cross the placenta, leading to the damage of the developing fetus. Studies on laboratory animals and clinical observations have demonstrated that ethanol diffuses through the placenta and is rapidly distributed, accumulating in amniotic fluid. The identification of various adverse effects of prenatal alcohol exposure remains a significant area of concern among scientists. The purpose of a study- is to conduct a qualitative and quantitative analysis of histological changes in cardiomyocytes of rat embryos during days 18-20 under condition of chronic alcohol intoxication in the maternal organism. Methods. The subjects of study were the hearts of offspring from rats during days 18-20 of prenatal development in a model of chronic maternal alcohol intoxication. Quantitative and qualitative parameters of cardiomyocyte myofibrils from different regions of the ventricular myocardium were assessed using transmission electron microscopy. Results. Our findings indicated that following ethanol exposure to the maternal organism, the orientation of damaged myofibrils in the offspring was chaotic and spread over significant areas of the sarcoplasm.Unlike normal conditions, the cardiomyocytes of experimental animals displayed not only myofibrils in a regular contracted or relaxed state, but also those with deformed sarcomeres exhibiting signs of excessive contraction and disorientation of fragmented myofilaments.The intracellular organelles of cardiomyocytes in the experimental group of newborns underwent significant and varied changes. Conclusions. Chronic alcohol intoxication during prenatal cardiogenesis damages the contractile apparatus of vebtricular cardiomyocytes due to the disorganization of sarcomere structure, fragmentation, and disorientation of myofibrils, significant suppression of sarcomerogenesis, and reduction of myofibril content, which is associated with mitochondrial distruction. The severity of changes in these structures depends on the region and developmental stage of the embryo.