Structural and functional changes in coronary arteries in chronic isoproterenol-induced cardiac ischemia

Abstract

Objective. To study the nature and sequence of development of pathomorphological processes in rat coronary arteries at different stages of modeling chronic cardiac ischemia.
Materials and methods. Chronic heart failure of ischemic genesis in Wistar rats was modeled by subcutaneous administration of β-adrenomimetic isoproterenol hydrochloride at a dose of 10 mg/kg/day for 14 days. In 4, 6 and 8 weeks after the last injection in experimental animals the features of morphofunctional changes in coronary vessels and the dynamics of changes in the activity of enzymes of cellular energy metabolism were analyzed.
Results. During the development of chronic isoproterenol-induced ischemic myocardial damage (from the 4th to the 8th week of the experiment), progression of structural changes in the vascular walls of rat coronary arteries was observed: both intima (deendothelialization and desquamation of endotheliocytes, focal subendothelial edema, disruption of the integrity of the outer and inner elastic membranes) and media and adventitia (dystrophy and necrobiosis of smooth muscle cells, loosening, edema, disorganization of layers, fibrosis) in combination with increasing sclerotic changes of perivascular spaces. Histochemical changes in endothelial cells of rat coronary vessels are manifested by a compensatory increase in lactate dehydrogenase activity by the 4th week of the experiment with a subsequent decrease in succinate and lactate dehydrogenase activity from the 6th to the 8th week of the experiment.
Conclusion. The morphological changes in rat coronary arteries have been revealed, which illustrate the dynamics of development of structural and functional changes in vessels in chronic isoproterenol-induced cardiac ischemia at late stages of its development. Structural changes in vascular walls are combined with a decrease in the efficiency of both aerobic and anaerobic pathways of energy formation.