CYTOCHEMICAL DEMONSTRATION OF SITES OF HYDROGEN-PEROXIDE GENERATION AND INCREASED VASCULAR-PERMEABILITY IN ISOLATED PIG HEARTS AFTER ISCHEMIA AND REPERFUSION

Isolated pig hearts, subsequently perfused with pig or human blood, we re prepared for the cytochemical demonstration of sites of hydrogen pe roxide generation and increased vascular permeability. Oxidant stress was associated with ultrastructural changes commonly seen following my ocardial reperfusion. In addition, the precipitation of cerium perhydr oxide following perfusion with physiological saline containing cerium chloride suggested the vascular endothelium and leukocytes as sources of oxidants. This was associated with rapid penetration of horseradish peroxidase through the intercellular clefts of the vascular endotheli um into the interstitial space, suggesting increased vascular leakines s at these sites. The rapid penetration of horseradish peroxidase was observed at all monitored periods of reperfusion with pig or human blo od. This indicates that the increased permeability occurred during the ischaemic period and continued during reperfusion. Morphological dama ge was greatest in pig hearts reperfused with whole human blood and th is was attenuated if the blood was preabsorbed to remove antibodies pr ior to reperfusion. We conclude that oxidant stress was initiated duri ng ischaemia and continued during reperfusion in this model. (C) 1998 Wiley-Liss, Inc.