Altered antioxidant status in ischemic/reperfused rabbit myocardium: reperfusion time-course study.
A progressive impairment in antioxidant status of rabbit hearts was observed when a fixed period (40 mins) of ischemia produced by coronary artery ligation was followed by increasing periods of reperfusion. This was reflected in a reduction in myocardial glutathione levels and an increase in glutathione depletion and production of thiobarbituric acid-reactive substances following in vitro oxidative challenge with t-butylhydroperoxide. Correlation analysis, in which activities of antioxidant enzymes were viewed in relation to biochemical indices of antioxidant status, indicated the functionally relevant suppression of Cu,Zn-superoxide dismutase and glutathione reductase activities in ischemic/reperfused tissues. These results and the demonstration of significant decreases in the activity of glutathione-dependent antioxidant enzymes under acidotic conditions suggest that transient impairment in the functioning of antioxidant enzymes may be involved in the triggering of irreversible myocardial ischemia-reperfusion injury.
Ko
K M
KM
Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver.
Garnett
M E
ME
Godin
D V
DV
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D005609:Free Radicals; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000201:enzymology*; D009206:Myocardium / Q000378:metabolism; D010545:Peroxides / Q000494:pharmacology; D011817:Rabbits; D013482:Superoxide Dismutase / Q000378:metabolism; D013858:Thiobarbiturates / Q000037:antagonists & inhibitors; D020122:tert-Butylhydroperoxide
D000975:Antioxidants; D005609:Free Radicals; D008054:Lipid Peroxides; D010545:Peroxides; D013858:Thiobarbiturates; D020122:tert-Butylhydroperoxide; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione