Oxygen derived radicals related injury in the heart during calcium paradox.

The effects of oxygen-derived radical scavengers (ODRS) on the heart was investigated during the calcium paradox. Perfusion with Ca2+-free medium caused cell separation at the intercalated discs and changes in the endothelial cells. Upon Ca2+ reintroduction, a massive cell damage occurred. The cytosolic enzyme, creatine phosphokinase (CPK), was released in large amounts (p less than 0.001). The tissue adenosine triphosphate (ATP) was reduced to 3.7 mumol/g dry weight from the control value of 21.6 mumol/g dry weight and tissue Ca2+ content was increased threefold. The treatment with superoxide dismutase (SOD) and catalase (CAT) increased percentage of normal cells (62.2%) compared to nontreated Ca2+ paradox group (0.2%) and caused negligible leakage of CPK. Tissue ATP was preserved (p less than 0.03), and Ca2+ content was also reduced in the hearts treated with SOD and CAT (p less than 0.03). The cell membranes and vascular endothelium were well preserved in the hearts treated with SOD and CAT. Boiled SOD and CAT administered were totally ineffective. It is suggested that oxygen-active species may have a role in the Ca2+ paradox injury.