白细胞介素-22激活Nrf2通路对肝纤维化小鼠结肠屏障的影响

Effect of IL-22 Activating Nrf2 Pathway on the Colonic Barrier in Mice with LiverFibrosis

目的研究白细胞介素(IL)-22对肝纤维化小鼠结肠屏障的影响及与Nrf2通路的关系。方法将小鼠分为对照组(CON组)、模型组(MOD组)、IL-22组、IL-22+ML385组(ML385为Nrf2抑制剂),每组10只,造模周期为8周。除CON组外,其余各组均给予含乙醇的液体饲料及四氯化碳橄榄油腹腔注射;IL-22组在此基础上给予IL-22;IL-22+ML385组于IL-22处理前1 h腹腔注射ML385。造模结束,对肝脏进行苏木精-伊红(HE)、马松(Masson)染色,明确是否发生纤维化;收集小鼠粪便,检测球菌与杆菌的比值,观察肠道菌群生长情况;对结肠进行HE染色、免疫荧光和免疫组织化学检测,分析紧密连接蛋白ZO-1、Occludin和Nrf2通路蛋白(Nrf2、HO-1、NQO1)表达情况。结果与CON组比较,MOD组小鼠肝组织呈现明显纤维化、结肠组织出现炎细胞浸润、紧密连接蛋白表达下降(P<0.05),粪培养基未见各种致病菌过度生长,球杆比值无明显差异。与MOD组比较,IL-22组肝脏及结肠组织病理损伤均减轻,紧密连接蛋白表达升高,Nrf2、NQO1、HO-1表达水平亦升高(P<0.05),IL-22+ML385组无明显改变。结论IL-22可改善肝纤维化小鼠结肠屏障功能,其机制与Nrf2抗氧化应激通路激活有关。

Objective To study the effect of IL-22 on the colonic barrier and its relationship with Nrf2 pathway in liver fibrosis mice.Methods The mice were divided into four groups:the control group(CON group),the model group(MOD group),the interleukin-22 group(IL-22 group),and the IL-22+ML385 group(ML385,an inhibitor of Nrf2),with 10 mice in each group,and the modeling cycle was 8 weeks.Liquid feed containing alcohol and carbon tetrachloride olive oil were given intraperitoneally in all groups except the CON group;IL-22 was given on top of this in the IL-22 group;and ML385 was injected intraperitoneally in the IL-22+ML385 group one hour before IL-22 treatment.At the end of modeling,the livers were stained with HE and Masson staining to clarify whether fibrosis occurred in the mice;the feces were collected to detect the cocci to bacillus ratio and observe the growth of intestinal flora;the colons were stained with HE staining,immunofluorescence and immunohistochemistry,and analyzed for the expression of tight junction proteins ZO-1,Occludin,and the Nrf2 pathway proteins(Nrf2,HO-1,and NQO1).The expression of these proteins was analyzed by immunohistochemistry.Results Compared with the CON group,mice in the MOD group showed significant fibrosis in the liver tissue,inflammatory cell infiltration in the colon tissue,and decreased expression of tight junction proteins(P<0.05).No overgrowth of various pathogenic bacteria was seen in fecal media.And there was no significant difference in the bulb-to-bar ratio.Compared with the MOD group,both liver and colon histopathologic damage were reduced in the IL-22 group,and tight junction protein expression was elevated,in addition,the expression levels of Nrf2,NQO1,and HO-1 were also elevated(P<0.05),whereas there was no significant change in the IL-22+ML385 group.Conclusion IL-22 improved the colonic barrier function in liver fibrosis mice,and the mechanism was related to the activation of Nrf2 anti-oxidative stress pathway.