细胞穿透肽PEP-1介导血红素加氧酶-1对大鼠肠缺血再灌注损伤的影响

Effects of heme oxygenase-1 mediated by cell penetrating peptide PEP-1 on intestinal ischemia/reperfusion injury in rats

目的评价细胞穿透肽PEP-1介导血红素加氧酶-1（HO-1）对大鼠肠缺血再灌注损伤的影响。方法雄性SD大鼠18只，周龄7-9周，体重210～260g，采用随机数字表法，将大鼠随机分为3组（n=6）：假手术组（S组）、肠缺血再灌注组（IR组）和融合蛋白PEP-1／HO-1＋肠缺血再灌注组（HO组）。采用夹闭肠系膜上动脉45min，恢复灌注120min的方法制备大鼠肠缺血再灌注损伤模型。HO组夹闭肠系膜上动脉前30min，左侧髂静脉注射融合蛋白PEP-1／HO-10．5mg，S组不夹闭肠系膜上动脉，余操作同IR组。于再灌注120min时处死大鼠取小肠组织，称重后计算肠湿／干重比，测定丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性和HO-1活性，免疫组化法检测肠组织HO-1蛋白的表达，光镜下观察肠组织结构并进行损伤评分。结果与s组比较，IR组和HO组肠湿，干重比和MDA含量升高，SOD活性降低，HO-1活性和蛋白表达水平升高，损伤评分升高（P〈0．05）；与IR组比较，HO组肠湿，干重比、MDA含量降低，SOD活性升高，HO-1活性和蛋白表达水平升高，损伤评分降低（P〈0．05）。HO组大鼠肠组织病理学损伤较IR组减轻。结论细胞穿透肽PEP-1可将HO-1成功导人大鼠肠组织中的细胞并减轻肠缺血再灌注损．伤。

Objective To investigate the effects of heme oxygenase-1 （HO-1） mediated by ceU penetrating peptide PEP-1 on intestinal ischemia/reperflsion （I/R） injury in rats. Methods Eighteen male SD rats aged 7- 9 weeks weighing 210-260 g were randomly divided into 3 groups （ n = 6 each） ： sham operation group （group S）, I/R group and PEP-1/HO-1 ＋ I/R group （group HO）. To establish a model of intestinal I/R injury, intestines were exteriorized and the superior mesenteric artery was exposed and occluded for 45 min ischemia, and then the clamp was removed for 120 rain reperfusion. The PEP-1/HO-1 fusion protein 0.5 mg was injected via the left iliac vein 30 min prior to ischemia in group HO. The superior mesenteric artery was exposed but not occluded in group S. At the end of reperfusion, the rats were sacrificed and intestinal tissues obtained to determine the intestinal wet/dry ratio, malondialdehyde （MDA） level, actizities of superoxide dismutase （SOD） and HO-1, and HO-1 protein expression. The histological changes in the intestinal mucosa were examined and the injury was scored. Results Compared with group S, the intestinal wet/dry tatio, MDA level, HO-1 activity, HO-1 protein expression and injury score were significantly increased, while the SOD activity was significantly decreased in groups I/R and HO （P 〈 0.05）. Compared with group I/R, the irtestinal wet/dry ratio, MDA level and injury score were significantly decreased, while the SOD activity, HO-1 actvity and HO-1 protein expression increased in group HO （ P 〈 0.05） . The pathologic changes were significanly attenuated in group HO compared with group I/R. Conclusion HO-1 protein can be successfully delivered into intestinal tissues by PEP-1 and has protective effects against intesti- nal I/R injury.