乌司他丁对脓毒血症大鼠肠黏膜屏障损伤的保护及其对Wnt信号通路的影响

目的 探讨乌司他丁（尿抑制素，UTI）能否对大鼠脓毒症肠黏膜损伤提供保护及其机制。 方法 选取SD大鼠100只，采用计算机软件随机分为对照组、脓毒症组、乌司他丁组、XAV939+乌司他丁组、氧化锂（LiCl ）+乌司他丁组。以经典盲肠结扎穿孔法建立脓毒症模型，检查评估空肠黏膜的损伤。采用酶联免疫吸附法(ELISA)检测炎症因子白细胞介素（IL-6）及肿瘤坏死因子（TNF-α）水平，采用Real-time PCR、Western blotting检测乌司他丁对β-连环蛋白（β-catenin）和细胞周期蛋白（cyclin D1）的表达情况；观察XAV939阻断或者LiCl激活Wnt信号通路对乌司他丁保护大鼠肠黏膜及Wnt信号通路相关蛋白的影响。 结果 脓毒症组IL-6、TNF-α水平及肠道黏膜损伤评分均显著高于乌司他丁组；脓毒症组β-catenin及cyclin D1的mRNA和蛋白表达水平均较对照组显著升高，差异具有显著性（P<0.05），给予乌司他丁处理之后，β-catenin及cyclin D1 mRNA和蛋白表达水平均显著降低，差异具有显著性（P<0.05）；与乌司他丁相比，XAV939促进了乌司他丁对大鼠肠黏膜的保护的作用，而且β-catenin和cyclin D1的蛋白表达降低（P<0.05）；LiCl减弱了乌司他丁对大鼠肠黏膜的保护作用，而且β-catenin和cyclin D1的蛋白表达升高，差异具有显著性（P<0.05）。 结论 乌司他丁通过下调β-catenin的表达抑制Wnt信号通路，降低炎症因子IL-6、TNF-α表达，从而改善脓毒症导致的肠黏膜屏障功能损伤。

Effects of ulinastatin on intestinal mucosal barrier function in sepsis rats and its effect on wnt signal transduction pathway

Objective To investigate the intestinal mucosal barrier function protective effect of ulinastatin in sepsis rats and its effect on Wnt/β-catenin signaling pathway. Methods One hundred SD rats were randomly divided into control group, sepsis group, ulinastatin group, XAV939+ulinastatin group and lithium chloride(LiCl)+ulinastatin group. The classical cecal ligation was used to duplicate sepsis model, and the jejunal mucosal injury was evaluated. The levels of inflammatory factors interleukin(IL)-6 and tumor necrosis factor(TNF)-α were detected by ELISA, and the expressions of β-catenin and cyclin D1 were detected by Real-time PCR and Western blotting. We also observed the effect of the Wnt signal pathway blockage by XAV939 or Wnt signal pathway activator by LiCl on ulinastatin protection of intestinal mucosa and proteins related to the Wnt signal pathway. Results The levels of IL-6, TNF-α and intestinal mucosal injury in the sepsis group were significantly higher than those in the ulinastatin group. The mRNA and protein expression levels of β-catenin and cyclin D1 in the sepsis group were significantly higher than those in the control group (P<0.05), After ulinastatin treatment, the expression levels of β-catenin and cyclin D1 mRNA and protein were significantly decreased, and the difference was significant (P<0.05). Compared with the ulinastatin group, combined treatment with XAV939 promoted the protective effect of ulinastatin on the intestinal mucosa of rats, and the protein expression of β-catenin and cyclin D1 was reduced (P<0.05). Combined treatment with LiCl weakened the protective effect of ulinastatin on the intestinal mucosa of rats, and the protein expression of β-catenin and cyclin D1 was increased (P<0.05). Conclusion Ulinastatin may inhibit the Wnt signaling pathway by down-regulating the expression of β-catenin, reduce the expression of inflammatory factors IL-6 and TNF-α, thereby promote repairing the intestinal mucosal barrier function damage.