黏附侵袭性大肠埃希菌LF82对溃疡性结肠炎小鼠肠道屏障结构和功能的影响  

Effects of adherent invasive Escherichia coli LF82 strain on the structure and function of intestinal barrier in mice with ulcerative colitis

作　　者：沙素梅 陈芬荣 汪永华 崔婷 吴开春 徐斌 Sha Sumei;Chen Fenrong;Wang Yonghua;Cui Ting;Wu Kaichun;Xu Bin(Department of Gastroenterology,The Second Affiliated Hospital of Xi′an Jiaotong University(Xibei Hospital),Xi′an 710004,China;The Fifth Department of Gastroenterology,Xijing Hospital of Digestive Diseases,Air Force Military Medical University,Xi′an 710032,China;Department of General Surgery,Chenggong Hospital Affiliated to Xiamen University,Xiamen 361003,China)

机构地区：[1]西安交通大学第二附属医院(西北医院)消化内科,710004 [2]空军军医大学西京消化病医院消化五科,西安710032 [3]厦门大学附属成功医院普通外科,361003

出　　处：《中华消化杂志》2020年第8期532-538,共7页Chinese Journal of Digestion

基　　金：国家自然科学基金青年项目(81500423、81502082);陕西省自然科学基础研究计划面上项目(2017JM8026)。

摘　　要：目的探讨黏附侵袭性大肠埃希菌(E.coli)LF82菌株对UC小鼠肠道屏障结构和功能的影响。方法将24只清洁级C57BL/6小鼠分为菌株UC组、UC组和健康对照组,每组8只。采用葡聚糖硫酸钠(DSS)诱导小鼠UC模型,造模前1周,给予菌株UC组小鼠1×109 CFU E.coli LF82菌株灌胃,使菌株定植。通过疾病活动指数(DAI)、结肠大体形态损伤评分、结肠黏膜损伤指数(CMDI)、结肠组织髓过氧化物酶(MPO)活性、组织病理学表现等比较E.coli LF82对UC小鼠结肠炎症的作用。通过透射电子显微镜和直接免疫荧光染色法观察3组小鼠结肠组织超微结构和细胞骨架F-肌动蛋白的变化,采用过碘酸希夫反应(PAS)染色和天狼星红染色评估结肠黏液分泌能力和纤维化程度。采用t检验、最小显著差异法、重复测量方差分析和单因素方差分析进行统计学分析。结果菌株UC组小鼠造模第4、5、6、7天DAI评分均高于UC组[分别为(2.53±0.38)分比(2.01±0.53)分、(3.02±0.62)分比(2.67±0.24)分、(3.13±0.61)分比(2.20±0.24)分、(3.27±0.28)分比(2.20±0.69)分],差异均有统计学意义(t=3.37、2.25、9.56、10.24,P均<0.05)。菌株UC组小鼠结肠的大体形态损伤评分高于UC组[(6.17±1.94)分比(2.83±0.98)分],差异有统计学意义(t=-3.75,P<0.05)。菌株UC组小鼠CMDI和结肠黏膜MPO活性均高于UC组[(16.80±2.79)分比(11.80±3.11)分、(729.3±77.5)U/mg比(594.4±31.9)U/mg],差异均有统计学意义(t=-2.83;均值差值为134.82,95%CI 72.12~197.51;P均<0.05)。透射电子显微镜下结果显示,菌株E.coli LF82可侵入小鼠肠上皮下,引起结肠组织进一步损伤,使结肠骨架蛋白F-肌动蛋白分布状况发生改变。PAS染色结果显示,菌株UC组和UC组PAS阳性细胞百分比低于健康对照组[(32.40±8.02)%、(41.90±8.99)%比(57.70±11.52)%],差异有统计学意义(F=17.63,P<0.01),菌株UC组PAS阳性细胞百分比低于UC组,差异有统计学意义(均值差值为-9.50,95%CI-18.33--0.67,Objective To investigate the effects of adherent-invasive Escherichia coli(E.coli)LF82 on the structure and function of intestinal barrier in mice with ulcerative colitis(UC).Methods Twenty-four specific pathogen free(SPF)C57BL/6 mice were divided into UC with E.coli LF82 group,UC group and healthy control group with eight mice in each group.The UC mice model was induced by dextran sulfate sodium(DSS).One week before modeling,the mice of UC with E.coli LF82 group were intragastric administrated with 1×109 colony-forming unit(CFU)E.coli LF82 to colonize the bacteria strain.The effects of E.coli LF82 on colitis of mice with UC were evaluated by disease activity index(DAI),gross morphological injury score,colonic mucosal injury index(CMDI),myeoloperoxidase(MPO)activity and pathological features.The ultrastructure and the changes of cytoskeleton F-actin of mice colonic tissues were detected by transmission electron microscope(TEM)and direct immunofluorescence.The ability of colonic mucin production and degree of fibrosis were estimated by periodic acid Schiff reaction(PAS)stain and sirius red stain.T test,least significant difference,repeated measurement analysis of variance and one-way analysis of variance were used for statistical analysis.Results On the fourth,fifth,sixth and seventh day after the modeling,the DAI scores of UC with E.coli LF82 group were all higher than those of UC group((2.53±0.38)points vs.(2.01±0.53)points,(3.02±0.62)points vs.(2.67±0.24)points,(3.13±0.61)points vs.(2.20±0.24)points,(3.27±0.28)points vs.(2.20±0.69)points,respectively),and the differences were statistically significant(t=3.37,2.25,9.56 and 10.24,all P<0.05).The gross morphological injury score of mice colon of UC with E.coli LF82 group was higher than that of UC group((6.17±1.94)points vs.(2.83±0.98)points),and the difference was statistically significant(t=-3.75,P<0.05).The CMDI and MPO activity of UC with E.coli LF82 group were both higher than those of UC group((16.80±2.79)points vs.(11.80±3.11)points,(729.3±77.

关 键 词：炎症性肠病 结肠炎 溃疡性 肠道细菌 黏附侵袭性大肠杆菌 小鼠 

分 类 号：R574.62[医药卫生—消化系统]