摘要目的:探讨硫化氢（H 2S）对小肠缺血/再灌注损伤（IRI）大鼠磷脂酰肌醇3 -激酶/蛋白激酶B（PI3K/Akt）信号通路表达的影响。 方法:将30只雄性Wistar大鼠按随机数字表法分为假手术组（Sham组）、IRI组、H 2S供体硫氢化钠（NaHS）干预组（IRI+NaHS组），每组10只。采用无损伤血管夹夹闭肠系膜上动脉（SMA）60 min、再灌注120 min的方法建立大鼠肠IRI模型；Sham组仅分离SMA后关腹。恢复SMA血流前10 min，IRI+NaHS组经尾静脉注入100 μmol/kg NaHS后以1.07 mmol·kg -1·h -1的速度维持输注至再灌注120 min；Sham组和IRI组则给予等体积生理盐水。实验结束后取下腔静脉血，采用敏感硫电极法测定血浆H 2S浓度。取血后处死大鼠取回肠组织，采用苏木素-伊红（HE）染色观察组织病理学改变并进行Chiu评分；用蛋白质免疫印迹试验（Western Blot）检测磷酸化Akt（p-Akt）、Akt、PI3K、活化的天冬氨酸特异性半胱氨酸蛋白酶9（caspase-9）、哺乳动物雷帕霉素靶蛋白（mTOR）蛋白表达。 结果:与Sham组比较，IRI组肠黏膜组织结构紊乱、水肿，绒毛断裂、脱落，病理评分明显升高（分：4.21±0.15比0.15±0.03， P<0.01），血浆H 2S水平明显降低（μmol/L：26.72±3.17比38.34±5.24， P<0.01），回肠组织p-Akt、PI3K、caspase-9、mTOR蛋白表达明显升高（p-Akt/GAPDH：2.67±0.12比0.24±0.05，PI3K/GAPDH：1.42±0.07比0.57±0.08，caspase-9/GAPDH：4.23±0.61比0.13±0.02，mTOR/GAPDH：2.17±0.23比0.23±0.02，均 P<0.01）。与IRI组比较，IRI+NaHS组肠黏膜病理改变减轻，病理评分明显下降（分：1.56±0.02比4.21±0.15， P<0.01），血浆H 2S水平明显升高（μmol/L：32.36±2.45比26.72±3.17， P<0.01），回肠组织p-Akt、PI3K蛋白表达进一步升高（p-Akt/GAPDH：5.12±0.08比2.67±0.12，PI3K/GAPDH：3.14±0.05比1.42±0.07，均 P<0.01），而caspase-9、mTOR蛋白表达明显降低（caspase-9/GAPDH：2.12±0.24比4.23±0.61，mTOR/GAPDH：1.37±0.28比2.17±0.23，均 P<0.01）。 结论:H 2S通过上调PI3K/Akt信号通路表达，下调caspase-9、mTOR表达，从而减轻IRI大鼠肠损伤。

abstractsObjective:To explore the effect of hydrogen sulfide (H 2S) on expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) signal pathway in rats with intestinal ischemia/reperfusion (IRI) injury. Methods:Thirty male Wistar rats were divided into sham operation group (Sham group), IRI group, and H 2S precursor sodium hydrosuphide (NaHS) intervention group (IRI+NaHS group) by random number table method, with 10 rats in each group. The animal model of IRI was established by 60 minutes superior mesenteric artery (SMA) blockage with non-invasive vascular clamp and 120 minutes reflow. SMA was dissociated and peritoneum cavity was closed in Sham group. The rats in IRI+NaHS group was received NaHS (100 μmol/kg bolus+1.07 mmol·kg -1·h -1 infusion) 10 minutes prior to the onset of reperfusion, while the rats in IRI group and Sham group were received equal volume of normal sodium. Blood in vena cava was collected. H 2S was detected by sensitive sulfide electrode. Rats were sacrificed after blood collection. Histopathology change was observed by hematoxylin-eosin (HE) staining, ileal pathological score was studied by Chiu score. The protein expressions of phosphated Akt (p-Akt), Akt, PI3K, cleaved caspase-9, mammalian target of rapamycin (mTOR) were determined by Western Blot. Results:Compared with the Sham group, there was intestinal mucosa structure disorder edema and shedding villous fracture in the IRI group. Ileal pathological score in IRI group was significantly increased (4.21±0.15 vs. 0.15±0.03, P < 0.01), while plasma H 2S in IRI group was significantly decreased (μmol/L: 26.72±3.17 vs. 38.34±5.24, P < 0.01). Ileal p-Akt, PI3K, caspase-9 and mTOR protein in IRI group were significantly increased (p-Akt/GAPDH: 2.67±0.12 vs. 0.24±0.05, PI3K/GAPDH: 1.42±0.07 vs. 0.57±0.08, caspase-9/GAPDH: 4.23±0.61 vs. 0.13±0.02, mTOR/GAPDH: 2.17±0.23 vs. 0.23±0.02, all P < 0.01). Compared with the IRI group, pathological changes of intestinal mucosa in the IRI+NaHS group was improved, ileal pathological score was significantly decreased (1.56±0.02 vs. 4.21±0.15, P < 0.01), plasma H 2S was significantly increased (μmol/L: 32.36±2.45 vs. 26.72±3.17, P < 0.01) and ileal p-Akt, PI3K were significantly increased (p-Akt/GAPDH: 5.12±0.08 vs. 2.67±0.12, PI3K/GAPDH: 3.14±0.05 vs. 1.42±0.07, both P < 0.01), while caspase-9, mTOR in IRI+NaHS group were significantly decreased (caspase-9/GAPDH: 2.12±0.24 vs. 4.23±0.61, mTOR/GAPDH: 1.37±0.28 vs. 2.17±0.23, both P < 0.01). Conclusion:H 2S attenuates intestinal injury in IRI rats by up-regulating PI3K/Akt signal pathway and down-regulating caspase-9 and mTOR.