iNOS enhances rat intestinal apoptosis after ischemia-reperfusion.
The aim of this study was to demonstrate (i) the role of iNOS (inducible nitric oxide synthase) on apoptosis in the rat intestinal mucosa after ischemia-reperfusion, and (ii) the effect of iNOS on the release of cytochrome c from mitochondria. The superior mesenteric artery was occluded for 60 min and was followed by a 60 min reperfusion. Rats were pretreated with an intraperitoneal injection of the following iNOS inhibitors: N-nitro-L-arginine methyl ester, aminoguanidine, and (1S,5S,6R,7R)-7- chloro-3-imino-5-methyl-2-azabicyclo [4. 1. 0] heptane hydrochloride (ONO-1714). Apoptosis was evaluated and NO(X) in the portal vein was assayed. The amount of iNOS, caspase-3, and cytochrome c were determined by a Western blot analysis. Intestinal mucosal epithelial mitochondrial dehydrogenase activity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoilium bromide. Ischemia-reperfusion increased intestinal mucosal apoptosis, NO(X) production in the portal vein, the amount of iNOS protein, and the release of cytochrome c, but not caspase-3. Inhibitors of iNOS significantly attenuated the induction of apoptosis, increased NO(X) production, and release of cytochrome c. Mitochondrial dysfunction was induced by ischemia-reperfusion, which was ameliorated by iNOS inhibitors. Our results indicate that iNOS is related to increased mucosal apoptosis in the rat small intestine after ischemia-reperfusion, which is partly explained by the release of cytochrome c from mitochondria to cytosols following mitochondrial dysfunction.
Department of Internal Medicine, Saga Medical School, Nabeshima, Saga, Japan.
Bin
B
Wu
Ryuichi
R
Iwakiri
Seiji
S
Tsunada
Hiroyoshi
H
Utsumi
Masataka
M
Kojima
Takehiro
T
Fujise
Akifumi
A
Ootani
Kazuma
K
Fujimoto
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D004587:Electrophoresis, Agar Gel; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D004848:Epithelium / Q000201:enzymology; D005609:Free Radicals; D007150:Immunohistochemistry; D007583:Jejunum / Q000473:pathology; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury
D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D005609:Free Radicals; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases