Hydrogen sulfide improves intestinal recovery following ischemia by endothelial nitric oxide-dependent mechanisms

Hydrogen sulfide (H 2 S) is an endogenous gasotransmitter that has vasodilatory properties. It may be a novel therapy for intestinal ischemia-reperfusion (I/R) injury. We hypothesized that 1 ) H 2 S would improve postischemic survival, mesenteric perfusion, mucosal injury, and inflammation compared with vehicle and 2 ) the benefits of H 2 S would be mediated through endothelial nitric oxide. C57BL/6J wild-type and endothelial nitric oxide synthase knockout (eNOS KO) mice were anesthetized, and a midline laparotomy was performed. Intestines were eviscerated, the small bowel mesenteric root identified, and baseline intestinal perfusion was determined using laser Doppler. Intestinal ischemia was established by temporarily occluding the superior mesenteric artery. Following ischemia, the clamp was removed, and the intestines were allowed to recover. Either sodium hydrosulfide (2 nmol/kg or 2 µmol/kg NaHS) in PBS vehicle or vehicle only was injected into the peritoneum. Animals were allowed to recover and were assessed for mesenteric perfusion, mucosal injury, and intestinal cytokines. P values < 0.05 were significant. H 2 S improved mesenteric perfusion and mucosal injury scores following I/R injury. However, in the setting of eNOS ablation, there was no improvement in these parameters with H 2 S therapy. Application of H 2 S also resulted in lower levels of intestinal cytokine production following I/R. Intraperitoneal H 2 S therapy can improve mesenteric perfusion, intestinal mucosal injury, and intestinal inflammation following I/R. The benefits of H 2 S appear to be mediated through endothelial nitric oxide-dependent pathways. NEW & NOTEWORTHY H 2 S is a gaseous mediator that acts as an anti-inflammatory agent contributing to gastrointestinal mucosal defense. It promotes vascular dilation, mucosal repair, and resolution of inflammation following intestinal ischemia and may be exploited as a novel therapeutic agent. It is unclear whether H 2 S works through nitric oxide-dependent pathways in the intestine. We appreciate that H 2 S was able to improve postischemic recovery of mesenteric perfusion, mucosal integrity, and inflammation. The beneficial effects of H 2 S appear to be mediated through endothelial nitric oxide-dependent pathways.