Radical production during in vivo intestinal ischemia and reperfusion in the cat.
Free radical formation was studied with electron spin resonance during 2 h of intestinal ischemia in the cat, at a blood flow less than 5 ml.min-1.100 g-1, followed by 30-min reperfusion. A modification of the spin trapping technique was used to stabilize highly reactive free radicals. The rate of secondary radical formation was 0.32 +/- 0.06 mumol.min-1.100 g intestine-1 before ischemia and increased to a maximum of 0.66 +/- 0.09 mumol.min-1.100 g-1 during the first minutes of reperfusion (mean +/- SE, n = 5). This could be prevented either by maintaining intestinal blood flow at 8-15 ml.min-1.100 g-1, by administering allopurinol before and during ischemia, or by perfusing the intestinal lumen with an O2-saturated buffer solution during ischemia, resulting in maximum rates of radical production during reperfusion of 0.37 +/- 0.04 (n = 6), 0.33 +/- 0.04 (n = 5), and 0.39 +/- 0.13 mumol.min-1.100 g-1 (n = 5), respectively. The results demonstrate that free radicals are produced in the intestine during reperfusion after a period of reduced blood flow below a certain critical level, and that inhibition of xanthine oxidase and prevention of hypoxia will eliminate this radical production.
Nilsson
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UA
Department of Biochemistry and Biophysics, Chalmers University of Technology, Gothenburg, Sweden.
Lundgren
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O
Haglind
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E
Bylund-Fellenius
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AC
D000818:Animals; D002415:Cats; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005260:Female; D005609:Free Radicals; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000098:blood supply* / Q000473:pathology; D007511:Ischemia / Q000378:metabolism* / Q000473:pathology; D008297:Male; D010080:Oxazoles / Q000378:metabolism; D015424:Reperfusion
D005609:Free Radicals; D010080:Oxazoles; C034589:2-ethyl-1-hydroxy-2,5,5-trimethyl-3-oxazolidine