酪酸梭菌与婴儿双歧杆菌对炎症性肠病小鼠肠道sIgA的影响

The effect of Clostridium butyricum and Bifidobacterium infantis on slgA in the intestine of IBD mice

目的建立三硝基苯磺酸（trinitro-benzene-sulfonic acid，TNBS）诱导的小鼠炎症性肠病（inflammatory bowel disease，IBD）模型，探讨肠道分泌型免疫球蛋白（secretory immunoglobulin A，sIgA）含量的变化与小鼠IBD发病的相互关系。研究酪酸梭菌（Clostridium butyricum，CB）、婴儿双歧杆菌（Bifidobacterium infantis，BB）分别或联合后对炎症状态下肠道sIgA的影响。方法采用简单随机法将小鼠分成5组：WT组、TNBS组、CB组、BB组和CB＋BB组，每组10只；2周后观察小鼠的一般状态和体重变化，处死小鼠收集结肠组织；进行HE染色，观察各组小鼠结肠炎症的情况；应用ELISA法检测肠液中的sIgA浓度；应用免疫组化法和Western blot法对结肠组织的sIgA进行定位和定量研究。结果TNBS组肠道炎症改变较WT组、CB组、BB组和CB＋BB组明显；在肠绒毛固有层中、肠腺腺腔内以及肠腺之间，都有sIgA的存在；TNBS组小鼠肠液和结肠组织中sIgA浓度水平均明显低于WT组（P均〈0.01）；CB、BB组小鼠肠液和结肠组织sIgA表达水平明显高于TNBS组（P均〈0.01），CB和BB两组之间比较差异无统计学意义（P均〉0.05） ；CB＋BB组小鼠肠液和结肠组织sIgA表达水平较CB组、BB组升高（P均〈0.01）。结论sIgA含量的变化与IBD的发生有关。CB和BB均能上调sIgA水平，改善IBD的肠道炎症反应，并且两菌联合比各自单独应用显示出更强的上调作用。

Objective To establish the inflammatory bowel disease model of mice by Trinitro-benzene- sulfonic acid（ TNBS ）. To investigate the correlation between the IBD and SIgA level and the effect of Clostridi- um butyricum,Bifidobacterium infantis single or combined on slgA expression. Methods BABL/c mice were randomly divided into. WT group, TNBS group, CB group, BB group and CB ＋ BB group. After 2 weeks, the general situation and weight change of mice was evaluated. Then the mice were sacrificed to collect colon tissue. The inflammation of each group was observed by HE staining. The expression of slgA were respectively located and measured by irnmunohistochemistry and Western blotting. Results TNBS group showed more pathological changes in the colon than the WT group, CB group, BB group and CB ＋ BB group;the expressions of slgA in co- lon were mainly located in intestinal lumen and lamina propria of intestinal villus; the level of slgA in colon and tissue decreased in the TNBS group compared with WT group（ P 〈 0.01 ; P 〈 0. 01 ） ; the level of slgA in colon and tissue increased in the CB group and BB group compared with TNBS group（P 〈0. 01 ;P 〈0. 01 ;P 〈0. 01; P 〈 0. 01 ）. There is no significant difference between CB group and BB group（ P 〉 0. 05 ）. The level of slgA in colon and tissue increased in the CB ＋BB group compared with CB group or BB group（P 〈0.01 ;P 〈0. 01 ）. Conclusion The change of slgA content is related to the occurrence of IBD. CB and BB can both promote slgA production in IBD mice and reduce the inflammatory reaction. The combination of the two probiotics shows stronger effect than single one.