吲哚乙酰化高直链玉米淀粉改善溃疡性结肠炎的作用机制研究

Mechanism of action indole acetylated high-amylose maize starch in improving ulcerative colitis

为了研究吲哚乙酰化高直链玉米淀粉改善溃疡性结肠炎的作用机制,利用葡聚糖硫酸钠诱导急性溃疡性结肠炎小鼠模型,采用吲哚乙酰化高直链玉米淀粉靶向结肠释放吲哚乙酸,结合芳香烃受体抑制剂,分析小鼠结肠长度、疾病活动指数,利用酶联免疫吸附法测定结肠白介素-6、白介素-10、转化生长因子β1、髓过氧化物酶和白介素-22等细胞因子的表达水平,采用定量聚合酶链反应分析结肠紧密连接蛋白occludin、ZO-1及CYP1A1的相对表达水平,并通过流式细胞术分析肠系膜淋巴结中调节性T细胞和辅助性T细胞17的比例。结果发现,吲哚乙酰化高直链玉米淀粉明显减轻结肠长度的缩短,显著降低疾病活动指数及白介素-6和髓过氧化物酶的表达,显著促进白介素-10、转化生长因子β1、白介素-22、CYP1A1、occludin和ZO-1的表达,明显提高调节性T细胞的比例,并显著降低辅助性T细胞17的比例,而给予芳香烃受体抑制剂会削弱吲哚乙酰化高直链玉米淀粉的作用。以上结果提示,吲哚乙酰化高直链玉米淀粉可通过激活芳香烃受体发挥改善溃疡性结肠炎的作用。

The aim of this study is to investigate the mechanism action of indole acetylated high-amylose maize starch in improving ulcerative colitis.Dextran sulfate sodium salt was used to induce acute ulcerative colitis in mice.Indole acetylated high-amylose maize starch was then used to target the colon with the delivery of indole-3-acetic acid.This was combined with the administration of an aryl hydrocarbon receptor inhibitor to analyze the mice in terms of colon length;disease activity index;and levels of interleukin-6,interleukin-10,transforming growth factorβ1,myeloperoxidase,and interleukin-22 in the colon,which were detected by enzyme-linked immunosorbent assay.Quantitative polymerase chain reaction was used to analyze the relative expression levels of the colonic tight junction proteins occludin,ZO-1,and CYP1A1.Flow cytometry was used to test the ratio of regulatory T cells and T helper 17 cells in the mesenteric lymph nodes.The results showed that administration of indole acetylated high-amylose maize starch significantly alleviated the shortening of the colon length;significantly reduced the disease activity index and the levels of interleukin-6 and myeloperoxidase;significantly promoted the expression of interleukin-10,transforming growth factorβ1,interleukin-22,CYP1A1,occludin,and ZO-1;significantly increased the proportion of regulatory T cells;and significantly reduced the proportion of T helper 17 cells.Administration of the aryl hydrocarbon receptor inhibitor weakened the effect of indole acetylated high-amylose maize starch.These results together suggest that acetylated high-amylose maize starch can improve ulcerative colitis by activating aryl hydrocarbon receptors.