PYRUVATE ENHANCES RECOVERY OF RAT HEARTS AFTER ISCHEMIA AND REPERFUSION BY PREVENTING FREE-RADICAL GENERATION

Pyruvate protects myocardium from ischemic and anoxic injury, effects that have been attributed to beneficial metabolic alterations. Pyruvat e also reacts with hydrogen peroxide in vitro, and pyruvate prevents f ree radical injury in other organs. Hearts supplied with 2 mM of pyruv ate with glucose during reperfusion recovered significantly more mecha nical function (81%) than those provided with 2 mM of acetate (which d oes not react with free radicals) and glucose (49%) or glucose alone ( 27%). Pyruvate significantly reduced free radical generation during re perfusion as measured with electron spin resonance using the spin-trap 5,5-dimethyl-1-pyrroline-1-oxide. In a model of direct oxidant stress , hearts were perfused with 0.28 mM of hydrogen peroxide. In this mode l, loss of function was almost entirely prevented by addition of 2 mM of pyruvate. From these results we conclude an important mechanism of protection when pyruvate is supplied during reperfusion is limitation of oxygen-derived free radical damage.