PATTERN OF SUPEROXIDE-DISMUTASE ENZYMATIC-ACTIVITY AND RNA CHANGES INRAT-HEART VENTRICLES AFTER MYOCARDIAL-INFARCTION

A multiplex reverse transcription polymerase chain reaction assay was designed to measure manganese super oxide dismutase (MnSOD) and CuZnSO D mRNAs in the left and right ventricles of rat hearts after myocardia l infarction induced by occlusion of the left coronary artery. These d ata were compared with changes in enzymatic activities. in the left ve ntricle, Mn-SOD RNA increased significantly at 6 hours, peaked at 12 h ears (490 +/- 38 arbitrary units), and progressively decreased (127 +/ - 21 arbitrary units at 48 hours), in contrast, there was a steady acc umulation of transcripts in the right ventricle up to 48 hours. in bot h ventricles, the changes in the MnSOD mRNA and protein content were n ot associated with proportional variations in enzymatic activity. Ther e was no characteristic alteration of the CuZnSOD system in either ven tricle over the 48-hour period. These results demonstrate that infarct ion selectively activates the MnSOD gene in the viable myocardium of b oth ventricles. They suggest that MnSOD may be involved in the adaptiv e response of myocytes to the overloading stress.