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

Amanda R Jensen, Natalie A Drucker, Sina Khaneki, Michael J Ferkowicz, Troy A Markel

Hydrogen Sulfide (H2S) is an endogenous gasotransmitter that has vasodilatory properties. It may be a novel therapy for intestinal I/R. We hypothesized that: 1) H2S would improve post-ischemic survival, mesenteric perfusion, mucosal injury, and inflammation compared to vehicle, and 2) the benefits of H2S would be mediated through endothelial nitric oxide. C57Bl6J wild type (WT) and endothelial nitric oxide synthase knock out (eNOS KO) mice were anesthetized and a midline laparotomy performed. Intestines were eviscerated, the small bowel mesenteric root identified, and baseline intestinal perfusion 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. Sodium hydrosulfide (NaHS) in 250µl of PBS or the vehicle was injected into the peritoneum. Animals were allowed to recover and were assessed for survival, mesenteric perfusion, mucosal injury, and intestinal cytokines. P-values less than 0.05 were significant. H2S improved survival at lower doses, while the high dose resulted in immediate demise. Mesenteric perfusion and mucosal injury scores were improved following I/R with low and mid-range H2S therapy. In the setting of eNOS ablation, there was no improvement in mesenteric perfusion or mucosal injury. H2S also resulted in lower levels of intestinal cytokines. Although high levels of hydrogen sulfide can result in mortality, appropriate doses can improve mesenteric perfusion and intestinal mucosal injury following I/R. The benefits of H2S appear to be mediated through endothelial nitric oxide dependent pathways.