Electronic-microscopic changes of the heart of old rats with hyperhomocystemia

Abstract

Annotation. Hyperhomocysteinemia (HHCys) is a pathological condition characterized by an increase in plasma homocysteine (HCys) levels above 15 μmol/l and causes abnormal functioning of the human body. Increasing the concentration of HCys in plasma can cause structural and functional changes in all organs and systems of the body, but, as research shows, the most vulnerable is the cardiovascular system. The aim of the research is to study the ultrastructural changes in the heart of old rats under conditions of HHCys. The experimental study was performed on 22 white nonlinear old (24-26 months) male rats. During the experiment, the animals were divided into two groups – control and experimental. Simulation of persistent HHCys was achieved by administering to rats the experimental group thiolactone HCys at a dose of 200 mg/kg body weight intragastrally for 60 days. Ultrathin sections were studied in the PEM – 125K electron microscope. It was found that the introduction of thiolactone HCys to old rats at a dose of 200 mg/kg is associated with the development of destructive-dystrophic changes in the heart of animals. They are visible in all layers of the organ in the form of a significant increase in the volume of connective tissue. The lumens of most hemocapillaries were dilated and filled with blood cells. In endotheliocytes there are severe ultrastructural disorders, manifested by the disappearance of micropinocytic vesicles and caveolae, the formation of large caveolae-like structures, which led to a violation of transcapillary metabolism. Intracellular edema, hypertrophied mitochondria with locally enlightened matrix, destroyed crystals, damaged outer membrane were found in cardiomyocytes. Myofibrils became thinner, they showed lysis of myofibrils.