AJP - Gastrointestinal and Liver Physiology, Vol 257, Issue 3 409-G414, Copyright © 1989 by American Physiological Society
Radical production during in vivo intestinal ischemia and reperfusion in the cat
U. A. Nilsson, O. Lundgren, E. Haglind and A. C. Bylund-Fellenius
Department of Biochemistry and Biophysics, Chalmers University of Technology, Gothenburg, Sweden.
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.
