Changes of Cardiac Structural Proteins in Myocardial Infarction

Abstract

Changes of structural proteins in experimental and human myocardial infarction were studied in the determination of myosin- and actomyosin-ATPase activities and gel electrophoretic analysis in the presence of sodium dodecyl sulfate (SDS). In experiments using dogs, the relative amounts of myosin and .alpha.-actinin decreased at 24-48 h after coronary ligation, became lowest at 72 h, and remained at this level for 2 wk and returned to almost normal value at 28 days. Myosin- and actomyosin-ATPase activities decreased rapidly during 24-48 h after ligation with temporary increase in their activities in the initial stage of ischemia and followed a course similar to that of the amounts of myosin and .alpha.-actinin. SDS gel electrophoretic analysis of structural proteins of infarcted tissues of the human hearts obtained from 5 cadavers also showed a marked decrease of the myosin and .alpha.-actinin contents with relative preservation of actin, tropomyosin and tropinin-T.