鞣花酸调控NLRP3/Caspase-1信号通路改善脂多糖诱导的小鼠肠道炎症

Ellagic acid regulated the NLRP3/Caspase-1 signaling pathway to ameliorate lipopolysaccharide-induced intestinal inflammation in mice

目的探讨鞣花酸(ellagic acid,EA)对脂多糖(lipopolysaccharide,LPS)诱导的小鼠肠道炎症的治疗作用和相关机制。方法通过随机数字法将18只雄性C57BL/6小鼠随机分为三组:对照组(CON)、LPS组和LPS-EA组每组6只。LPS组和LPS-EA组小鼠腹腔注射LPS(4 mg/kg),CON组注射等量生理盐水。腹腔注射后12 h,LPS-EA组连续7 d以EA(20 mg/kg)灌胃,CON组和LPS组以等量DMSO灌胃。第7天,测量各组小鼠空腹体质量,在灌胃2 h后,对各组小鼠实施安乐死,取血并取出结肠组织。HE染色光学显微镜下观察结肠组织病理变化。ELISA法测定小鼠血清IL-1β、IL-18水平,Western blotting法测定结肠组织中ZO-1、Occludin、NLRP3、Caspase-1蛋白表达水平。结果与CON组相比,LPS组小鼠结肠ZO-1、Occludin蛋白表达水平显著降低,血清IL-1β、IL-18水平及结肠组织中的NLRP3、Caspase-1蛋白表达水平显著升高。与LPS组相比,EA上调ZO-1、Occludin蛋白表达水平,下调小鼠血清IL-1β、IL-18水平以及结肠组织中的NLRP3、Caspase-1蛋白表达水平。结论EA修复肠黏膜屏障,抑制NLRP3炎症小体活化,下调Caspase-1表达水平,显著改善LPS诱导的小鼠急性肠道炎症。

Objective To investigate the therapeutic effect and the related mechanisms of ellagic acid(EA)on lipopolysaccharide(LPS)induced intestinal inflammation in mice.Methods 18 male C57BL/6 mice were randomly divided by the random number method into three groups:control(CON),LPS,and LPS-EA groups,with six mice in each group.The mice in the LPS and LPS-EA groups were injected intraperitoneally with LPS(4 mg/kg),and the CON group was injected with the same amount of saline.12 hours after intraperitoneal injection,the LPS-EA group was gavaged with ellagic acid(20 mg/kg)for 7 consecutive days,while the CON group and LPS group were gavaged with an equal amount of DMSO.On day 7,the fasting body weight of each group was measured,and 2 hours after gavage,the mice in each group were euthanized,and blood and colonic tissues were removed.After HE staining,the histopathological changes in the colon were observed under light microscopy.The levels of serum IL-1β and IL-18 were measured by ELISA,and the expression levels of ZO-1,Occludin,NLRP3 and Caspase-1 in the colon tissues were measured by Western blotting.Results Compared with the CON group,the colonic ZO-1 and Occludin protein expression levels were significantly lower in the LPS group,and the serum IL-1β and IL-18 levels as well as NLRP3 and Caspase-1 protein expression levels in the colonic tissues were significantly higher in the LPS group.Compared with the LPS group,EA up-regulated ZO-1 and Occludin protein expression levels and down-regulated serum IL-1β and IL-18 levels as well as NLRP3 and Caspase-1 protein expression levels in the colonic tissues of mice.Conclusion EA repaired the intestinal mucosal barrier,inhibited NLRP3 inflammasome activation,down-regulated caspase-1 expression levels,and significantly improved LPS-induced acute intestinal inflammation in mice.