木香烃内酯对溃疡性结肠炎小鼠肠道免疫炎症的影响及其机制

Effect and mechanism of Aucklandia lactone on intestinal immune inflammation in mice with ulcerative colitis

目的:观察木香烃内酯对溃疡性结肠炎(UC)小鼠肠道菌群及Th1/Th2失衡的影响。方法:将50只C57BL/6小鼠随机分为空白组、模型组、柳氮磺胺吡啶(SASP)组,木香烃内酯低剂量、高剂量组,每组10只。采用DSS法建立UC模型,SASP组及木香烃内酯低、高剂量组连续灌胃相应药物7 d,观察小鼠一般状况、疾病活动度指数(DAI)和结肠长度变化;HE染色观察结肠组织形态学改变;细菌培养鉴定法比较粪便中大肠杆菌、双歧杆菌、乳酸杆菌的数量;ELISA测定血清IL-6、TNF-α、IL-10水平,RT-qPCR检测结肠组织IL-6、TNF-α、IL-10的mRNA表达;Western blotting检测结肠组织TLR-4、NF-κB p65的蛋白表达。结果:与空白组比较,模型组小鼠DAI评分显著升高,结肠长度明显缩短,结肠黏膜结构损伤严重,炎性细胞浸润明显,粪便中大肠杆菌数值明显增多,双歧杆菌及乳酸杆菌数量明显减少,IL-6、TNF-α血清和结肠组织的mRNA水平明显升高,IL-10水平和mRNA表达显著降低,结肠组织中TLR-4、NF-κB p65的蛋白表达量明显增多(均P<0.01);与模型组相比,木香烃内酯灌胃干预显著降低了UC小鼠DAI评分,明显增长了结肠长度,结肠组织病理损伤有效改善,粪便中大肠杆菌数值减少,双歧杆菌及乳酸杆菌数量增加,降低了IL-6、TNF-α的血清水平和结肠组织mRNA表达,升高IL-10水平和mRNA表达,同时降低了结肠组织TLR-4、NF-κB p65的蛋白表达(P<0.01或P<0.05)。结论:木香烃内酯对UC小鼠症状具有明显的改善作用,其机制可能与改善肠道菌群状态,调节Th1/Th2细胞因子平衡,抑制TLR4/NF-κB的激活相关。

Objective:To observe the effects of Aucklandia lactone on intestinal flora and Th1/Th2 imbalance in mice with ulcerative colitis(UC).Methods:Fifty C57BL/6 mice were randomly divided into blank group,model group,sulfasalazine(SASP)group,and low-dose and high-dose Aucklandia lactone groups,with 10 rats in each group.The UC model was established by using dextran sulphate sodium(DSS).The drugs were given by gavage for 7 days.The general condition,disease activity index(DAI)and colon length were observed and compared.HE staining was used to observe the histomorphological changes of colon.The number of Escherichia coli,Bifidobacterium and Lactobacillus in feces was analyzed by bacterial culture.The serum contents and mRNA expressions of IL-6,TNF-αand IL-10 were determined by ELISA and the mRNA expressions of IL-6,TNF-αand IL-10 in colon were determined by RT-qPCR.The protein expressions of TLR-4 and NF-κB p65 were detected by western blotting.Results:Compared with the blank group,obvious inflammatory cell infiltration and seriously damaged colonic mucosal structure were noted in the model group,the DAI score,the number of Escherichia coli in feces,the IL-6 and TNF-αcontents in serum,the IL-6 and TNF-αmRNA expressions and the protein expressions of TLR-4 and NF-κB p65 in colon tissues were significantly increased,while the colon length,the number of Bifidobacteria and Lactobacillus,and the mRNA and serum protein levels of IL-10 were markedly decreased(P<0.01).Compared with the model group,Aucklandia lactone significantly reduced the DAI score,the number of Escherichia coli in feces,the IL-6 and TNF-αmRNA levels and the protein expressions of TLR-4 and NF-κB p65 in colon tissues,but elevated the length of colon,improved the pathological damage of colon,increased the number of Bifidobacteria and Lactobacillus as well as the level of IL-10(P<0.05 or P<0.01).Conclusion:Aucklandia lactone can significantly improve the symptoms of UC mice.Its mechanism may be related to improving the state of intestinal flora,regulating the balance of Th1/Th2 cytokines,and inhibiting TLR4/NF-κB activation.