食物过敏对大鼠小肠形态学及肠黏膜淋巴细胞的影响

Influence of Food Allergy on Small Intestinal Morphology and Intestinal Mucosal Lymphocytes in Rats

目的观察卵蛋白经口致敏的大鼠小肠(十二指肠、空肠、回肠)形态学及肠道黏膜内淋巴细胞(CD4+、CD8+T淋巴细胞、CD20+B淋巴细胞)变化的情况。方法将27只大鼠按随机数字表法分为2组:实验组(17只)和对照组(10只)。对照组大鼠以无菌PBS液灌胃。实验组大鼠以卵蛋白灌胃,建立肠道食物过敏的动物模型。HE染色观察食物过敏大鼠十二指肠、空肠、回肠病理学变化的情况,免疫组织化学法和体视学方法检测大鼠十二指肠、空肠、回肠肠黏膜CD4+、CD8+T淋巴细胞、CD20+B淋巴细胞免疫反应阳性细胞的分布和数量变化的情况。结果实验组大鼠十二指肠、空肠、回肠均可见肠绒毛出现不同程度的糜烂、肿胀、脱落现象,固有层见嗜酸性粒细胞、浆细胞等炎症细胞浸润。与对照组比较,实验组大鼠十二指肠、空肠、回肠肠绒毛均变短、萎缩(P<0.05或P<0.01);十二指肠、空肠肠腺均增长(P<0.05或P<0.01)。实验组大鼠十二指肠、空肠、回肠肠黏膜固有层CD4+T淋巴细胞数密度略低于对照组,但差异均无统计学意义(均P>0.05);实验组大鼠十二指肠、空肠、回肠肠黏膜固有层、上皮内CD8+T淋巴细胞数密度均明显低于对照组(P<0.05或P<0.01),实验组大鼠十二指肠、空肠、回肠肠黏膜固有层CD20+B淋巴细胞数密度均明显高于对照组(P<0.05或P<0.01)。结论卵蛋白致敏大鼠小肠肠黏膜损伤明显,肠黏膜淋巴细胞的变化导致肠黏膜局部免疫失调,在食物过敏变态反应性炎症发病过程中可能发挥重要的作用。

Objective To observe the changes in small intestinal morphology and intestinal mucosal lymphocytes in orally ovalbumin-sensitized rats.Methods Twenty-seven rats were randomly divided into two groups.Rats in control group（n=10） were intragastrically administered sterile PBS.Rats in experimental group（n=17） were intragastrically administered ovalbumin to establish an animal model of intestinal food allergy.Pathological changes in duodenum,jejunum and ileum were observed by HE staining.The distribution and numbers of intestinal mucosal CD4＋,CD8＋ and CD20＋ cells were detected by immunohistochemical and stereological methods.Results Various degrees of erosion,swelling and ablation of intestinal villi and infiltration of eosinophils,plasma cells and other inflammatory cells were observed in the duodenum,jejunum and ileum in experimental group.Compared with control group,intestinal villi of the duodenum,jejunum and ileum significantly shortened and atrophied and glands of duodenum and jejunum obviously overgrew in experimental group（P0.05 or P0.01）.The number of CD4＋ T lymphocytes in intestinal lamina propria of duodenum,jejunum and ileum in experimental group was slightly lower than that in control group,but the difference was not statistically significant（P0.05）.The number of CD8＋ T lymphocytes in intestinal epithelium and lamina propria of duodenum,jejunum and ileum in experimental group was significantly lower than that in control group（P0.05 or P0.01）.However,the number of CD20＋ B lymphocytes in intestinal lamina propria of duodenum,jejunum and ileum in experimental group was significantly higher than that in control group（P0.05 or P0.01）.Conclusion Ovalbumin-sensitized rats exhibit obvious small intestinal mucosal injury.The changes in intestinal mucosal lymphocytes cause local intestinal immune disorders,which may play an important role in the pathogenesis of allergic inflammation in food allergy.