Evidence for a reversible oxygen radical-mediated component of reperfusion injury: Reduction by recombinant human superoxide dismutase administered at the time of reflow

G. Ambrioso, Myron Weisfeldt, W. E. Jacobus, J. T. Flaherty

Research output: Contribution to journalArticle

Abstract

It has been suggested that the beneficial effects of reperfusing ischemic myocardium might be in part reversed by the occurrence of 'reperfusion injury'. One possible mechanism could be the generation of oxygen free radicals. Superoxide dismutase enzymatically scavenges superoxide radicals by dismutation to hydrogen peroxide. This study tested the hypothesis that administration of recombinant human superoxide dismutase (h-SOD) at the time of reflow after a period of prolonged global ischemia would result in improved recovery of myocardial metabolism and function by preventing or reducing a potentially harmful component of reperfusion. We also sought to determine whether catalase, an enzymatic scavenger of hydrogen peroxide, was a necessary addition for optimal benefit. Langendorff perfused rabbit hearts were subjected to 30 min of normothermic (37° C) total global ischemia. At the moment of reperfusion, 12 control hearts received a 10 ml bolus of normal perfusate followed by 15 min of reperfusion with normal perfusate (group I), 12 hearts received 60,000 IU of h-SOD as a bolus followed by a continuous infusion of 100 IU/ml for 15 min (group II), and 12 hearts received 60,000 IU of h-SOD and 60,000 IU of catalase as a bolus followed by 100 IU/ml of both enzymes for 15 min (group III). Myocardial ATP and phosphocreatine (PCr) content and intracellular pH during ischemia and reperfusion were continuously monitored with 31P nuclear magnetic resonance (NMR) spectroscopy. During 30 min of normothermic global ischemia intracellular pH dropped from 7.11-7.18 to 5.58-5.80 in all three groups of hearts. Likewise myocardial PCr content fell rapidly to 7% to 8% and ATP fell more slowly to 29% to 36% of preischemic control content. After 45 min of reperfusion PCr recovered to 65 ± 5% of control in untreated (group I) hearts compared with 89 ± 8% in h-SOD-treated (group II) hearts (p

Original languageEnglish (US)
Pages (from-to)282-291
Number of pages10
JournalCirculation
Volume75
Issue number1
Publication statusPublished - 1987

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ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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