表没食子儿茶素没食子酸酯通过抑制NLRP3炎症小体改善溃疡性结肠炎小鼠肠道屏障的研究

EGCG improves intestinal barrier in mice with ulcerative colitis by inhibiting NLRP3 inflammasome

目的研究表没食子儿茶素没食子酸酯(EGCG)对溃疡性结肠炎小鼠肠道屏障的影响,并探讨其机制。方法雄性C57BL/6J小鼠随机分为正常(CON)组、模型(DSS)组、模型+低剂量EGCG(LEG)组和模型+高剂量EGCG(HEG)组,每组8只。给予含3%葡聚糖硫酸钠(DSS)的饮用水建立溃疡性结肠炎小鼠模型,LEG组和HEG组分别给予50、100 mg/kg EGCG灌胃,CON组和DSS组给予生理盐水灌胃。7 d后,测定小鼠疾病活动指数(DAI)评分和结肠长度,检测血清中白介素1β(IL-1β)、白介素6(IL-6)和白介素10(IL-10)水平,HE染色观察结肠组织病理变化,RT-qPCR法检测ZO-1和occludin mRNA表达,Western blot法检测核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)和caspase-1蛋白表达水平。结果与CON组相比,DSS组小鼠结肠长度缩短,DAI评分、血清中促炎因子水平、NLRP3和caspase-1蛋白表达均明显增高,血清IL-10含量、ZO-1和occludin mRNA表达下降。与DSS组比较,EGCG各干预组小鼠上述指标均有所改善。结论EGCG可改善溃疡性结肠炎小鼠结肠屏障损伤和炎症反应,可能与抑制NLRP3炎症小体的活化相关。

Objective To investigate the effect of epigallocatechin-3-gallate(EGCG)on the intestinal barrier in ulcerative colitis mice and explore its mechanism.Methods Male C57BL/6J mice were randomly divided into the normal(CON)group,the model(DSS)group,the model+low-dose EGCG(LEG)group,and the model+high-dose EGCG(HEG)group,with 8 mice in each group.A mouse model of ulcerative colitis(UC)was established by administering drinking water containing 3%dextran sulfate sodium.The LEG and HEG groups were gavaged with 50 and 100 mg/kg EGCG,while the CON and DSS groups were gavaged with normal saline.After 7 days,the levels of disease activity index(DAI),colon length,and IL-1β,IL-6 and IL-10 in serum were detected.The pathological changes of colon tissue were observed by H&E staining.The mRNA expression of zonulaoccludens-1(ZO-1)and occludin in colon tissue was detected using RT-qPCR.The protein expression levels of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)and caspase-1 were detected using Western blot.Results Compared with the CON group,the DSS group had a shortened colon length.DAI score,serum pro-inflammatory factor levels,and NLRP3 and caspase-1 protein expression were significantly increased.The concentration of serum IL-10 and the levels of ZO-1 and occludin mRNA expression were decreased.Compared with the DSS group,EGCG treatment showed improvements in the above indicators in UC mice.Conclusion EGCG can improve colonic barrier damage and inflammatory response in UC mice,and the mechanisms might be associated with the inhibition of the NLRP3 inflammasome activation.