Protective action of selenium and manganese on xanthine and xanthine oxidase induced oxidative damage to cultured heart cells.

Ventricular myocytes from neonatal Wistar rats were cultured with 80% Dulbecoo's modified Eagle medium and 20% fetal bovine serum. An appropriate amount of xanthine and xanthine oxidase was added to the culture medium to increase the content of free radicals in cardiac cells. Variation in action potential and input impedance of cardiac myocytes indicated the oxidative damage to the membrane. The ultrastructure of heart cells, characteristically the myofilaments and mitochondria, was damaged. Electron spin resonance measurement demonstrated that xanthine and xanthine oxidase elevated the free radical content, while selenium (Se) and manganese (Mn) reduced the free radicals in cultured heart cells. Supplementation of 0.173 microgram/ml Se and 0.1 microgram/ml Mn into the culture medium separately or simultaneously antagonized the damage induced by xanthine and xanthine oxidase. The possible mechanism might be the production of superoxide anion free radical leading to free radical damage to cardiac cells. Se and Mn might play a role as scavengers through glutathione peroxidase and superoxide dismutase respectively and thus protect cardiac cells from free radical damage.