Abstract
Systemic inflammatory response syndrome, as a consequence of ischemia/reperfusion (I/R), negatively influences the function of the affected organs. The objective of this study was to assess the role of nitric oxide (NO) in remote intestinal inflammatory response elicited by hindlimb I/R. To this end, C57BL/6 (wild type; WT) and inducible nitric-oxide synthase (iNOS)-deficient mice were subjected to bilateral hindlimb ischemia (1 h) followed by 6 h of reperfusion. Some WT mice were injected with iNOS inhibitor N-[3-(aminomethyl)benzyl] acetamidine (1400W) (5 mg/kg s.c.) immediately before reperfusion, and proinflammatory response was assessed 6 h later. Hindlimb I/R resulted in dysfunction of the small intestine as assessed by the increase in permeability [blood-to-lumen clearance of Texas Red-dextran (molecular mass 3 kDa)] and an increase in the luminal levels of tumor necrosis factor (TNF)-α protein and nitrate/nitrite (). The above-mentioned changes were accompanied by up-regulation of the proinflammatory phenotype in the mucosa of small intestine with respect to 1) an increase in TNF-α and iNOS protein expression, 2) leukocyte accumulation, 3) formation of edema, 4) an increase in leukocyte rolling/adhesion in the submucosal microvasculature, and 5) activation of transcription factor nuclear factor-κB and up-regulation of adhesion molecule expression. Interestingly, the most profound changes with respect to intestinal dysfunction were found in jejunum and ileum, whereas duodenum was affected the least. Interfering with iNOS activity (1400W and iNOS-deficient mice) significantly attenuated hindlimb I/R-induced inflammatory response and dysfunction of the small intestine with respect to the above-mentioned markers of inflammation. The obtained results indicate that hindlimb I/R induces remote inflammatory response in the small intestine through an iNOS-derived NO-dependent mechanism.
Footnotes
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This work was supported by the Heart and Stroke Foundation of Ontario, Canada [Research Grants HSFO-NA5580, HSFO-NA6171] (to G.C.); and the Canadian Institutes for Health Research [Grant MOP-68848] (to R.F.P.).
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R.F.P. and G.C. contributed equally to this work.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.108.148460.
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ABBREVIATIONS: SIRS, systemic inflammatory response syndrome; MODS, multiple organ dysfunction syndrome; I/R, ischemia/reperfusion; NOS, nitric-oxide synthase; nNOS, neuronal nitric-oxide synthase; eNOS, endothelial nitric-oxide synthase; iNOS, inducible nitric-oxide synthase; 1400W, N-[3-(aminomethyl)benzyl] acetamidine; PBS, phosphate-buffered saline; TNF, tumor necrosis factor; ELISA, enzyme-linked immunosorbent assay; ICAM, intercellular adhesion molecule; NF-κB, nuclear factor-κB; EMSA, electrophoretic mobility shift assay; E-64, N-(trans-epoxysuccinyl)-l-leucine 4-guanidinobutylamide; WT, wild type; MPO, myeloperoxidase.
- Received November 10, 2008.
- Accepted March 5, 2009.
- The American Society for Pharmacology and Experimental Therapeutics
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