Abstract
Reactive oxygen species are suggested to participate in ischemia-reperfusion (I-R) injury. However, induction of inducible nitric oxide synthase (iNOS) and production of high levels of nitric oxide (NO) also contribute to this injury. NO can combine with superoxide to form the potent oxidant peroxynitrite (ONOO−). NO and ONOO− were investigated in a rat model of renal I-R injury using the selective iNOS inhibitorl-N6-(1-iminoethyl)lysine (l-NIL). Sprague-Dawley rats were subjected to 40 min of bilateral renal ischemia followed by 6 h of reperfusion with or without l-NIL administration. Control animals received a sham surgery and had plasma creatinine values of 0.4 ± 0.1 mg/dl. I-R surgery significantly increased plasma creatinine levels to 1.9 ± 0.3 mg/dl (P < .05) and caused renal cortical necrosis. l-NIL administration (3 mg/kg) in animals subjected to I-R significantly decreased plasma creatinine levels to 1.2 ± 0.10 mg/dl (P < .05 compared with I-R) and reduced tubular damage. ONOO− formation was evaluated by detecting 3-nitrotyrosine-protein adducts, a stable biomarker of ONOO− formation. Immunohistochemistry and HPLC revealed that the kidneys from I-R animals had increased levels of 3-nitrotyrosine-protein adducts compared with control animals.l-NIL-treated rats (3 mg/kg) subjected to I-R showed decreased levels of 3-nitrotyrosine-protein adducts. These results support the hypothesis that iNOS-generated NO mediates damage in I-R injury possibly through ONOO− formation.
Footnotes
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Send reprint requests to: Philip R. Mayeux, Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Mail slot 611, Little Rock, AR 72205. E-mail: mayeuxphilipr{at}exchange.uams.edu
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↵1 This study was supported by an American Heart Association Heartland Affiliate Predoctoral Fellowship to L.M.W. and by National Institutes of Health Grant DK44716.
- Abbreviations:
- ARF
- acute renal failure
- I-R
- ischemia-reperfusion
- ONOO−
- peroxynitrite
- NO
- nitric oxide
- NOS
- nitric oxide synthase
- iNOS
- inducible nitric oxide synthase
- l-NIL
- l-N6-(1-iminoethyl)lysine
- PAS
- periodic acid-Schiff
- Received March 17, 2000.
- Accepted June 19, 2000.
- U.S. Government
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