同型半胱氨酸调控MEK-ERK-MLCK通路影响结肠炎大鼠肠黏膜通透性的实验研究

摘要

目的：探讨同型半胱氨酸( homocysteine, Hcy)是否通过调控MEK-ERK-MLCK通路影响结肠炎大鼠肠黏膜通透性的机制。方法 SD大鼠分为4组,A组为正常对照组( NS皮下注射+NS灌肠), B组为正常对照+Hcy注射组( Hcy皮下注射+NS灌肠),C组为TNBS模型组( NS皮下注射+TNBS灌肠),D组为TNBS模型+Hcy注射组( Hcy皮下注射+TNBS灌肠)。建立高 Hcy 血症的实验性结肠炎大鼠模型,实验结束时取大鼠结肠组织病理学检查,并进行结肠匀浆检测MPO活性,采用Western blot方法检测大鼠小肠组织中MEK、ERK、p-ERK、MLCK、p-MLCK的蛋白表达水平,采用RT-qPCR方法检测大鼠小肠组织中MLCK mRNA表达。结果与正常对照组及模型对照组相比,TNBS模型+Hcy皮下注射组大鼠DAI及HI评分增高,结肠匀浆MPO活性增高,小肠黏膜组织MEK、ERK、p-ERK、MLCK、p-MLCK蛋白表达水平增加,MLCK mRNA相对表达量增加。结论 Hcy增加实验性结肠炎大鼠肠黏膜通透性,可能与调控MEK-ERK-MLCK信号通路有关。%Aim To investigate whether Hcy influenced the intestinal mucosal permeability by regulating MEK-ERK-MLCK pathway. Methods SD rats were divided into 4 groups:normal group, normal+Hcy group, TN-BS/ethanol group, TNBS/ethanol+Hcy group. Experi-mental colitis model with hyperhomocystinemia was es-tablished in rats with intracolonic administration of TN-BS and subcutaneous injection of Hcy. The colonic mucosal tissue was collected for histopathological exam-ination and activity of myeloperoxidase ( MPO ) . The protein expression of MLCK, p-MLCK, MEK, ERK and p-ERK in intestinal mucosal tissues was examined by Western blot method. The mRNA expression of ML-CK was examined by RT-qPCR method. Result Com-pared with the normal group and TNBS group, the DAI and HI scores and the MPO activity were increased in TNBS/ethanol+Hcy group ( P <0. 01 ) . Western blot and RT-qPCR showed that expression of MLCK, p-ML-CK, MEK, ERK and p-ERK increased in small intes-tine in TNBS/ethanol+Hcy group. Conclusion Hcy can increase intestinal permeability in TNBS-induced colitis rats by regulating the expression of MEK-ERK-MLCK signal pathway.