Journal article
Ascorbyl Free Radical as a Real-time Marker of Free Radical Generation in Briefly Ischemic and Reperfused Hearts: An Electron Paramagnetic Resonance Study
Circulation research, Vol.74(4), pp.650-658
04/1994
DOI: 10.1161/01.RES.74.4.650
PMID: 8137501
Abstract
The role of free radicals in myocardial reperfusion injury remains controversial. We have developed a new method using ascorbyl free radical (AFR) as a real-time, quantitative marker of free radical generation during myocardial reperfusion. A total of 35 dogs were studied. Twelve open-chest dogs underwent either 5 minutes (n=5) or 20 minutes (n=7) of coronary artery occlusion and 30 minutes of reperfusion. Seven additional animals undergoing 20 minutes of coronary occlusion also received the antioxidant enzymes superoxide dismutase and catalase, beginning 10 minutes before occlusion through the end of reperfusion. Exogenous ascorbate was infused intravenously, and the concentration of AFR in the great cardiac vein was continuously measured by electron paramagnetic resonance spectroscopy. Preocclusion AFR concentration was similar in the three groups. Upon reperfusion, AFR rose significantly in each animal group (P<.05). However, the AFR rise in the 20-minute-occlusion group, 38±17%, was significantly greater than in the 5-minute-occlusion group, 27±14% (P<.002). In addition, in the animals that received superoxide dismutase and catalase, the rise in the AFR was markedly attenuated, 13±6% (P<.002). Two dogs that received ascorbate but did not undergo coronary artery occlusion/reperfusion sequences showed no change in coronary venous AFR signal, indicating the stability of the signal over time. Five dogs received ascorbate while undergoing interventions to alter coronary venous flowintravenous saline, dobutamine, dipyridamole, and nitroglycerin. Coronary venous AFR changes were minimal despite large coronary flow alterations, indicating that the AFR signal is independent of changes in coronary venous flow. An additional 5 dogs, which underwent a 20-minute occlusion/reperfusion sequence without receiving ascorbic acid infusion, showed myocardial dyskinesis at 30 minutes after reperfusion that was similar in extent and severity to that in the dogs that received ascorbic acid for AFR measurement, suggesting that exogenous ascorbate at the doses given does not attenuate stunning during the initial minutes of reperfusion. In 4 dogs undergoing prolonged (60-minute) coronary occlusion, the rise in AFR was attenuated, 13±9% versus 38±17% in the 20-minute coronary occlusion group (P<.05), possibly as a result of necrosis of the radical-generating cellular components. We conclude that AFR is a reliable, real-time, quantitative marker of free radical generation during myocardial reperfusion after brief coronary occlusion.
Details
- Title: Subtitle
- Ascorbyl Free Radical as a Real-time Marker of Free Radical Generation in Briefly Ischemic and Reperfused Hearts: An Electron Paramagnetic Resonance Study
- Creators
- Mukesh Sharma - Cardiovascular Division (M.K.S., K.T.S., R.EK), Department of Internal Medicine, and ESR Center (G.R.B.), College of Medicine, the University of Iowa, Iowa CityGarry BuettnerKirk SpencerRichard Kerber
- Resource Type
- Journal article
- Publication Details
- Circulation research, Vol.74(4), pp.650-658
- DOI
- 10.1161/01.RES.74.4.650
- PMID
- 8137501
- NLM abbreviation
- Circ Res
- ISSN
- 0009-7330
- eISSN
- 1524-4571
- Publisher
- American Heart Association, Inc
- Language
- English
- Date published
- 04/1994
- Academic Unit
- Radiation Oncology
- Record Identifier
- 9984047724502771
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