Abstract: Objective To explore the effects of hydrogen sulfide(H2S) on apoptosis of intestinal mucosal epithelial cells during ischemia/reperfusion in rats and discuss the potential mechanisms. Methods The superior mesenteric artery was separated and blocked from the root using vascular clamp for 1 hour,then remove the clamp to restore blood supply,which accomplish duplicating intestinal ischemia/reperfusion animal model. Twenty-four male SD rats were randomly divided into3 groups with 8 rats in each group:Sham-operation control group(C group),Ischemia/reperfusion group(I/R group) and H2 S pretreatment group(Na HS group). Collect blood and intestinal tissue samples to assay the levels of superoxidase dismutase(SOD),malondialdehyde(MDA) and glutathione peroxidase(GSH-Px) after 2 hour reperfusion. The intestinal mucosal injury and histological alteration under through HE staining was observed. TUNEL method was used to detect apoptosis cells. Caspase-3 protein was measured by Western blot. Results Compared with C group,the damage of small intestinal mucosal tissue and gland was obvious in both I/R group and Na HS group,the levels of SOD and GSH-Px in serum and intestinal tissue was significantly decreased,cell apoptosis index(AI),MDA levels and caspase-3 protein expression were increased significantly. H2 S pretreatment markedly alleviated the pathological damage of small intestinal mucosal tissue,reduced the number of apoptosis cells,decreased the levels of MDA and caspase-3 protein expression,and promoted the levels of SOD and GSH-Px(P < 0. 01),as compared with I/R group. Conclusion H2 S can relieve the injury of intestinal mucosal tissues after ischemia/reperfusion,reduce the intestinal mucosal epithelial cells apoptosis,which maybe relates to its relieving the oxidative stress reaction during ischemia/reperfusion.