Influence of oxygen radicals generated by xanthine oxidase in the isolated perfused rat heart

Abstract

To investigate the cardiac effects of enzymatically generated oxygen radicals isolated Langendorff rat heart preparations were perfused with hypoxanthine (0.96 mmol X litre-1) plus xanthine oxidase (0.025 U X ml-1). Oxygen radicals produced an immediate increase in coronary flow. After 10 min a pronounced reduction in contractile performance, as well as in concentrations of high energy phosphates, was seen. Electron microscopical examination showed damage with cellular oedema as a prominent finding. These effects were all effectively reversed by the specific enzymes, superoxide dismutase and catalase, proving that they were due to oxygen radicals.