[Role of nitric oxide synthase III and guanosine 3':5'- cyclic monophosphate in the protection exerted by nitric oxide on hepatic ischemia-reperfusion injury].
Nitric oxide (NO) exerts cytoprotective effects against hepatic ischemia-reperfusion damage. This study was designed to evaluate which isoform of NO synthase (NOS) is implicated in the generation of cytoprotective NO and to investigate whether NO effects are mediated by cyclic GMP (cGMP). After partial ischemia for 45 min, liver damage was estimated by the release into plasma of cytolytic enzymes. Ischemia-reperfusion induced marked increases in plasma creatine kinase and lactate dehydrogenase after 1 h of reperfusion and of aminotransferases after 6 h of reperfusion. The pretreatment of ischemic rats with 8-bromo-cGMP (16 mg/kg i.v. 30 min before ischemia) or with L-arginine (the endogenous precursor of NO, 100 mg/kg i.v.) significantly diminished the ischemia-reperfusion-induced release of all these enzymes. This demonstrates that cGMP possesses hepatoprotective properties. By immunohistochemistry, we observed, after 6 h of reperfusion, an increase in endothelial NOS-III immunoreactivity, particularly in the small arteries and sinusoids. This NOS-III accumulation in endothelial cells could protect the liver against ischemia-reperfusion by the local generation of NO probably via cGMP.
Galen
F X
FX
Département d'endocrinologie, UFR des sciences pharmaceutiques et biologiques, université Paris-V, 4, France. galen@pharmacie.univ-paris5.fr
Cottart
C H
CH
Souil
E
E
Dinh-Xuan
A T
AT
Vaubourdolle
M
M
Nivet
V
V
Clot
J P
JP
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D003402:Creatine Kinase / Q000097:blood; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D004730:Endothelium, Vascular / Q000201:enzymology; D007150:Immunohistochemistry; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008099:Liver / Q000098:blood supply*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000517:prevention & control*
C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D001120:Arginine; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D003402:Creatine Kinase; D006152:Cyclic GMP