Protective effect of zinc against catecholamine-induced myocardial changes electrocardiographic and ultrastructural studies
Singal, P.K.; Dhillon, K.S.; Beamish, R.E.; Dhalla, N.S.
Laboratory Investigation; a Journal of Technical Methods and Pathology 44(5): 426-433
1981
ISSN/ISBN: 0023-6837 PMID: 7230729 Document Number: 176946
The effects of parenteral administration of Zn, 10 mg ZnSO4 twice/day for 7 days, on isoproterenol-induced ECG and ultrastructural changes in the myocardium of rats were studied. Increases in PR and QRS intervals due to isoproterenol (total dose, 80 mg/kg s.c.) were not seen in Zn-treated rats. Increased mortality and heart hypertrophy due to isoproterenol were reduced by Zn treatment. Isoproterenol-induced ultrastructural changes seen in most of the subendocardium and in portions of the subepicardium were restricted to focal areas of the subendocardium in Zn-treated animals. Necrotic areas of the subendocardium in Zn and isoproterenol-treated animals exhibited numerous phagocytotic cells and some muscle cells in this area showed lamellar bodies. Certain muscle fibers in the subendocardium of Zn and isoproterenol group, which appeared normal at the light microscope level, revealed focal cytoplasmic abberations by EM due to the presence of membrane-bound electron-dense bodies. Zn was partially protective against catecholamine-induced myocardial necrosis.