Radical production during in vivo intestinal ischemia and reperfusion in the cat
Nilsson, U.A.; Lundgren, O.; Haglind, E.; Bylund-Fellenius, A.C.
American Journal of Physiology 257(3 Pt 1): G409-G414
1989
ISSN/ISBN: 0002-9513 PMID: 2551184 Document Number: 337199
Free radical formation was studied with electron spin resonance during 2 h of intestinal ischemia in the cat, at a blood flow < 5 ml .cntdot. min-1 .cntdot. 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 .mu.mol .cntdot. min-1 100 g intestine-1 before ischemia and increased to a maximum of 0.66 .+-. 0.09 .mu.mol .cntdot. 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 .cntdot. 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 reperfusing of 0.37 .+-. 0.04 (n = 6), 0.33 .+-. 0.04 (n = 5), and 0.39 .+-. 0.13 .mu.mol .cntdot. 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.