Attenuation of ischemic preconditioning in pigs by scavenging of free oxyradicals with ascorbic acid

1 Institute of Pathophysiology, Center of Internal Medicine, University of Essen Medical School, 45122 Essen; and 2 Institute of Organic Chemistry, University of Essen, 45117 Essen, Germany Free oxyradicals are involved in the signal transduction of ischemic preconditioning in rats and rabbits. Data from larger mammals in which the infarct development is closer to that in humans are lacking. We have therefore investigated the impact of the radical scavenger ascorbic acid on ischemic preconditioning in pigs. In 33 anesthetized pigs, the left anterior descending coronary artery was perfused from an extracorporeal circuit. Infarct size (measured as percent area at risk) was determined by triphenyltetrazolium chloride staining. In placebo-treated animals undergoing 90 min of severe ischemia and 120 min of reperfusion, infarct size averaged 26.9 ± 3.9% (mean ± SE; n = 9). Ischemic preconditioning by 10 min of ischemia and 15 min of reperfusion reduced infarct size to 6.4 ± 2.4% ( P