肾上腺髓质素及其结合蛋白改善梗阻性黄疸大鼠肠黏膜屏障功能的作用

摘要

Objective To observe the protection effect of adrenomedullin(AM)and adrenomedullin binding protein-1 (AMBP-1) on the intestinal mucosal barrier after obstructive jaundice.Methods 24 male Sprague-Dawley rats were randomly divided into the Sham group,obstructive jaundice control group(Vehicle)and AM/AMBP-1 treatment group(n=8).Obstructive jaundice was in-duced in adult rats(180-220 g)by common bile duct ligation(CBDL).On 6 d after CBDL,the rats were administered through fem-oral vein with AM/AMBP-1(24/80μg/kg).Blood and tissue samples were collected at 24 h after administered AM/AMBP-1 for various measurements.The intestinal permeability of all rats was measured by fluorescein isothiocyanate-dextran(FITC-D).Serum concentration of TNF-αwas measured by enzyme-linked immunosorbent assay.The apoptosis of intestinal cells was detected by ter-minal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL).The expression of cleaved caspase-3 was measured by Western blot.The inj ury condition in the small intestinal mucosa was assessed by the Chiu′s scoring under microscope.Results Compared with the Sham group,the permeability of intestinal mucosa in the Vehicle group was increased (P<0.05)and serum TNF-αlevel was increased obviously (P<0.05).The expression of cleaved caspase-3 protein,the apoptosis index(AI)and the Chiu′s score were increased in the Vehicle control group(P<0.05).Compared with the Vehicle control group,the permeability of intestinal mucosa was significantly improved (P<0.05),serum TNF-αwas decreased in the AM/AMBP-1 group(P<0.05).The expression of cleaved caspase-3,the AI index and Chiu′s score were significantly decreased in the AM/AMBP-1 group(P<0.05). Conclusion AM and AMBP-1 can significantly improve the high permeability state of the intestinal mucosa in obstructive jaundice rat,reduce the apoptosis of the small intestinal tissue,alleviate the systemic inflammatory reaction and have the protective effect on the intestinal mucosal barrier.%目的：观察肾上腺髓质素（AM）及 AM结合蛋白（AMBP-1）对梗阻性黄疸后肠黏膜屏障的保护作用。方法将雄性SD大鼠24只，分为3组（n＝8）：假手术（Sham）组、梗阻性黄疸对照（Vehicle）组、梗阻性黄疸治疗（AM/AMBP-1）组。于胆道结扎术后第6天，经股静脉输入 AM和 AMBP-1，24 h后取材检测各项指标。用异硫氰酸荧光素-葡聚糖（FITC-D）检测肠黏膜通透性，用 ELISA试剂盒检测血清肿瘤坏死因子-α（TNF-α）的水平，采用原位脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（TUNEL）检测小肠组织细胞的凋亡情况，采用免疫印迹法检测小肠组织 cleaved caspase-3的蛋白表达情况，光镜下采用 Chiu′s评分法评测小肠黏膜损伤情况。结果 Vehicle组较 Sham组大鼠肠黏膜通透性增高（P＜0．05），血清 TNF-α的水平增高（P＜0．05），cleaved caspase-3的蛋白表达及凋亡指数增加（P＜0．05），肠黏膜损伤评分增加（P＜0．05）。AM/AMBP-1组与 Vehicle组比较，肠黏膜通透性有明显改善（P＜0．05），血清TNF-α的水平降低（P＜0．05），cleaved caspase-3的蛋白表达减少（P＜0．05），凋亡指数下降（P＜0．05），肠黏膜损伤Chiu′s评分降低（P＜0．05）。结论 AM与AMBP-1可以明显改善梗阻性黄疸大鼠肠黏膜的高通透性状态，降低小肠组织的细胞凋亡，减轻全身炎症反应，具有保护肠黏膜屏障作用。