Role of iNOS‐derived nitric oxide (NO) on hind limb ischemia/reperfusion (I/R)‐induced remote injury to the gut

Abstract

Systemic inflammatory response syndrome (SIRS), as a consequence of ischemia/reperfusion (I/R) negatively influences the function of the affected organs. In this study we assessed the potential mechanisms (role of NO) of remote intestinal inflammatory response elicited by hind limb I/R. To this end C57BL/6 (WT) and iNOS−/− mice were subjected to 1h of bilateral hind limb ischemia followed by 6h of reperfusion. Some WT mice were injected (s.c.) with iNOS inhibitor, 1400W (5mg/kg) immediately before induction of ischemia. The obtained results indicate that hind limb I/R results in dysfunction of the gut as assessed by the increase in total protein levels (Bradford assay), TNF-a protein (ELISA) and NO (Griess reaction) in the lumen of small intestine. In addition, hind limb I/R results in an increase in leukocyte accumulation (intravital microscopy and MPO assay), TNF-a and iNOS protein expression (Western blots) in the mucosa of small intestine. Important to note, that the most profound changes with respect to the gut dysfunction were found in jejunum and ileum, whereas duodenum was affected the least. Interfering with iNOS activity (1400W and iNOS−/− mice) significantly attenuated hind limb I/R-induced leukocyte recruitment to the gut mucosa and dysfunction of the small intestine. Taken together these data indicate that hind limb I/R induces remote inflammatory response in the small intestine through iNOS-derived NO dependent mechanism (HSFO-NA5580 and MOP-68848)