TNBS诱导炎症性肠病大鼠结肠神经元tau蛋白磷酸化以及COX-2表达的变化

目的:探讨三硝基苯磺酸(trinitrobenzene sulfonic acid,TNBS)诱导炎症性肠病(inflammatory bowel disease,IBD)模型大鼠结肠神经元tau蛋白磷酸化和环氧合酶2(COX-2)表达的变化。方法:30只健康雄性成年Wistar大鼠随机分为对照组、IBD模型组和TNBS组,每组10只,IBD模型组以TNBS乙醇连续灌肠14 d造模,对照组和TNBS组分别以等量生理盐水和TNBS灌肠;观察大鼠的一般情况和结肠病理组织学改变,用anti-Hu作为神经元标志以免疫荧光法检测结肠黏膜下神经元的数量变化,免疫荧光双染色检测结肠黏膜下神经元COX-2和磷酸化tau231、tau262的表达变化。结果:与对照组比较,IBD模型组大鼠结肠黏膜下神经元数量明显减少(P0.05),神经元tau蛋白磷酸化程度明显升高(P0.05),而TNBS组大鼠神经元数量与对照组相比无显著差别;对照组和TNBS组大鼠结肠黏膜下神经元几乎不表达COX-2,IBD模型组大鼠结肠神经细胞胞核和胞浆中均有COX-2的表达,与对照组和TNBS组相比有显著差异(P0.05)。结论:TNBS乙醇诱导IBD模型大鼠结肠黏膜下神经元减少,可能与tau蛋白高度磷酸化及COX-2表达有关。

Changes in phosphorylation of tau protein and COX-2 expression in colon submucosal neurons of IBD model rats induced by TNBS

AIM: To investigate the change of phosphorylation of tau protein and expression of cyclooxygenase 2 (COX-2) in colon submucosal neurons of enteric nerve system in inflammatory bowel disease (IBD) rats induced by trinitrobenzene sulfonic acid (TNBS). METHODS: Male rats (n=30) were randomly assigned to 3 groups (n=10 each): control group, IBD group and TNBS group. The IBD rats were induced by TNBS+ethanol enema for 14 d. The control and TNBS rats were given an equal volume of saline and TNBS, respectively. The general situation and the histopathologic change of the rat colon were observed. Immunofluorescence was used to check the change of phosphalated tau protein and COX-2 expression in the submucosal neurons of the colon. The expression of COX-2 and phosphorylated tau231 and tau262 in the rat colon submucosal neurons was observed by double immunofluorescence staining. RESULTS: Compared with control group, the number of neurons in the colon of IBD rats decreased obviously and the expression of phospholated tau231 and tau262 was significantly increased. The number of neurons in the colon of TNBS rats showed no significant difference compared with control rats. The rat neurons in control group and TNBS group did not express COX-2. COX-2 expression was observed in the nucleus and cytoplasm of colonic neurons in IBD rats, which showed significantly different from control and TNBS rats. CONCLUSION: The decreased neurons in the enteric nerve system of IBD rats might be associated with the phosphorylation of tau protein and the expression of inducible COX-2.