Reactive species in ischemic rat lung injury: contribution of
peroxynitrite.
Ischiropoulos, Harry, Abu B. Al-Mehdi, and Aron B. Fisher.
Institute for Environmental Medicine, University of Pennsylvania,
School of Medicine, Philadelphia, Pennsylvania 19104
APStracts 2:0047L, 1995.
Lung ischemia-reperfusion represents a potentially important mechanism
for diverse forms of tissue injury associated with decreased
pulmonary flow. Previous studies demonstrated oxidative injury in
ischemic reperfused lungs. The present study was designed to evaluate
the contribution of nitric oxide and peroxynitrite in tissue injury.
The levels of the stable decomposition products of nitric oxide and
peroxynitrite, nitrite plus nitrate, were 2-fold greater than control
during reperfusion following 60 min of ischemia. Inhibition of nitric
oxide synthesis by endotracheal insufflation of 5 mM NG-nitro-L
-arginine methyl ester, 30 minutes prior the induction of ischemia,
decreased the production of lung thiobarbituric acid reactive
substances (TBARS) by 67% (p<0.05, n=5), TBARS released into the
lung perfusate by 55% (p<0.05, n=5), lung conjugated dienes by 61%
(p<0.05, n=5) and dinitrophenylhydrazine-reactive protein carbonyl
levels by 86% (p<0.05, n=5). Amino acid analysis of tissue
homogenates from lungs exposed to 60 min of ischemia and 60 min of
reperfusion revealed a 1.8 fold (p<0.05, n=5) increase in
nitrotyrosine concentration as compared to 2 h continuously perfused
lungs. Inhibition of nitric oxide synthesis abolished the increase in
nitrotyrosine levels. Furthermore, lungs exposed to 60 min of
reperfusion after 60 min of ischemia showed specific binding of an
anti-nitrotyrosine antibody. In reperfused tissues, antibody binding
was observed throughout the lung. The binding was blocked with excess
of nitrotyrosine and minimal binding was observed in non-perfused
blood free control lungs. These results indicate that a strong
oxidant derived from nitric oxide consistent with the reactivity of
peroxynitrite contributes to the oxidative injury of isolated rat
lung from ischemia-reperfusion.
Received 10 January 1995; accepted in final form 24 March 1995.
APS Manuscript Number L007-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 4 April 1995.