Expression of ryanodine receptor mRNA and sarcoplasmic Ca²⁺-ATPase mRNA in the myocardium and intracellular reorganization of cardiomyocytes in dyslipidemia and during verapamil treatment.

Abstract

In experiments on rats, atherogenic diet led to hypercholesterolemia, while addition of verapamil to the diet led to the development of hypertriglyceridemia in these animals. Dyslipidemia induced significant changes in the cardiomyocyte ultrastructure (lytic changes in myofibrils and sarcoplasmic matrix and aggravation of autophagocytosis) that were most pronounced after addition of mercazolyl alone to the diet. After 30-day atherogenic diet, we observed a decrease in the relative content of RyR2 mRNA (by 67-73%, p<0.01) and SERCA2a mRNA (by 75-91%, p<0.01) in the myocardium. In 64 days these parameters remained reduced: by 64-72% (p<0.05) and 54-62% (p<0.05), respectively. Verapamil treatment reduced the severity and number of lytic lesions in cardiomyocytes, induced considerable glycogen accumulation in the sarcoplasm and its sequestration, promoted normalization, and prevented pronounced decrease of the relative RyR2 mRNA and SERCA2a mRNA in rat myocardium.