Expression of Ca(2+)-ATPase in sarcoplasmic reticulum in rat cardiomyocytes during experimental postinfarction cardiosclerosis and diabetes mellitus.

Abstract

We studied the expression of Ca(2+)-ATPase in sarcoplasmic reticulum of rat cardiomyocytes during isolated and combined development of postinfarction cardiosclerosis and diabetes mellitus. Postinfarction cardiosclerosis was formed within 6 weeks after coronary artery occlusion. Diabetes mellitus developed within 6 weeks after intraperitoneal injection of streptozotocin (60 mg/kg). Ca(2+)-ATPase in homogenate of rat myocardium was assayed by immunoblotting. Ischemic and diabetic remodeling of the myocardium was associated with reduced expression of Ca(2+)-ATPase in the sarcoplasmic reticulum. Combined pathology was characterized by minimum decrease in the level of this protein. It was concluded that induction of diabetes mellitus at the early stage of postinfarction cardiosclerosis triggered adaptive mechanisms that prevent the decrease in Ca(2+)-ATPase level in the sarcoplasmic reticulum of cardiomyocytes.