胰高血糖素样肽-2对肠大部切除术后残余肠管黏膜的损伤机制

Injury mechanism of glucagon-like peptide 2 on residual intestinal mucosa after massive bowel resection

目的胰高血糖素样肽-2(GLP-2)在肠大部分切除术(MBR)后机制研究甚少。文中旨在探讨自噬在大鼠GLP-2干预MBR后残余肠管粘膜损伤形成过程的作用。方法雄性Sprague-Dawley大鼠60只,随机分为假手术组(横断肠管但不切除,n=12)、MBR组(切除约80%肠管后行端端吻合,n=12)、GLP-2干预组(连续3 d经腹腔内注射GLP-2,n=12)、GLP-2干预MBR组(接受MBR后连续3 d经腹腔内注射GLP-2,n=8)、雷帕霉素组(接受MBR前30 min额外给予雷帕霉素,n=8)、3-甲基腺嘌呤组(接受MBR前30 min额外给予3-甲基腺嘌呤,n=8)。首先通过免疫组化测定MBR术后残余肠管GLP-2受体和自噬相关蛋白的表达;其次通过组织病理学评分评估GLP-2干预后残余肠管粘膜组织的损伤;最后在GLP-2干预的前提下分别给予自噬的激活和抑制剂,测定残余肠管粘膜组织自噬流的变化。结果与假手术组、GLP-2干预MBR组相比,MBR组GLP-2受体的表达明显下降(P<0.05)。与假手术组相比,MBR组自噬相关蛋白LC3的表达明显升高(P<0.01)。与MBR组相比,GLP-2干预MBR组LC3在GLP-2干预后表达亦明显升高(P<0.05)。与假手术组、GLP-2干预MBR组Chiu′s评分(2.42±0.16、3.54±0.36)相比,MBR组(8.52±0.26)明显升高(P<0.05)。与GLP-2干预MBR组相比,雷帕霉素组自噬相关蛋白LC3Ⅰ转化至LC3Ⅱ的比例明显增高(P<0.05),P62的表达则明显降低(P<0.05);3-甲基腺嘌呤组LC3Ⅰ转化至LC3Ⅱ的比例明显降低(P<0.05),P62的表达则明显增高(P<0.05)。结论GLP-2通过激活其受体相关信号通路调控自噬相关蛋白的表达可促进MBR术后残余肠管粘膜修复,自噬相关信号通路参与GLP-2激活其受体干预MBR术后残余肠管粘膜损伤的病理生理过程。

Objective There are few studies on the mechanism of glucagon-like peptide 2(GLP-2)after massive bowel resection(MBR).The purpose of this study was to explore the role of autophagy in the formation of residual intestinal mucosal injury after the intervention of GLP-2 in rats with MBR.Methods 60 male Sprague Dawley rats were randomly divided into sham operation group(intestinal transection without resection,n=12),MBR group(end-to-end anastomosis after resection of about 80%of the bowel,n=12),GLP-2 intervention group(intraperitoneal injection of GLP-2 for 3 consecutive days,n=12),GLP-2 intervention MBR group(intraperitoneal injection of GLP 2 for 3 consecutive days after MBR,n=8),rapamycin group(additional rapamycin was given 30min before receiving MBR,n=8),3-methyladenine group(additional 3-methyladenine was given 30min before receiving MBR,n=8).Firstly,the expression of GLP-2 and autophagy-associated protein in residual intestine after MBR was detected by immunohistochemistry.Secondly,the injury of residual intestinal mucosa was evaluated by histopathological score after the intervention of GLP-2.Finally,autophagy was activated and inhibitor was given with the intervention of GLP-2,and the changes of autophagy flow in residual intestinal mucosa were measured.Results Compared with sham operation group and GLP-2 intervention MBR group,the expression of GLP receptor in MBR group decreased significantly(P<0.05).The expression of autophagy-associated protein LC3 in MBR group was significantly higher than that in sham operation group(P<0.01).Compared with MBR group,the expression of LC3 in GLP-2 intervention MBR group was also significantly increased after the intervention of GLP-2(P<0.05).The Chiu's score of MBR group was significantly higher than that of sham operation group and GLP-2 intervention MBR group(2.42±0.16,3.54±0.36).In rapamycin group,the transformation rate of autophagy associated protein LC3Ⅰto LC3ⅠI was significantly higher(P<0.05)and the expression of P62 was significantly lower(P<0.05).In 3-methyladenine group,the transformation rate of LC3Ⅰto LC3ⅠI was significantly decreased(P<0.05),while the expression of P62 was significantly increased(P<0.05).Conclusion GLP-2 can promote the repair of residual intestinal mucosa after MBR by activating its receptor-related signal pathway and regulating the expression of autophagy-related proteins.Autophagy-related signaling pathway is involved in the pathophysiological process of GLP 2 activating its receptor to interfere with residual intestinal mucosal injury after MBR.