鼠伤寒沙门氏菌诱导昆明小鼠肠道感染模型的建立

目的:建立鼠伤寒沙门氏菌诱导昆明小鼠肠道感染模型。方法:先用5 mg/mL链霉素预处理2 d,提高小鼠对鼠伤寒沙门氏菌的敏感性,然后正常饲养1 d,攻毒前禁水禁食4 h,再分别以不同剂量灌胃攻毒2次,间隔24 h。观察小鼠临床症状,并通过组织病理切片、透射电镜和免疫组织化学的方法,分别观察小鼠肠道组织病理变化、小肠上皮细胞超微结构变化及肠道淋巴细胞增殖状况。结果:攻毒后昆明小鼠会出现昏睡、食欲不振、寒颤,甚至死亡的现象,解剖后发现小鼠肠道充血膨胀。组织病理切片显示小鼠肠粘膜受损,小肠绒毛肿胀,排列杂乱,炎性细胞浸润;透射电镜观察超微结构显示小肠上皮细胞线粒体空泡化,嵴和膜发生融合消失,粗面内质网发生扩张;免疫组织化学的方法显示肠道感染后,淋巴结肿大,T淋巴细胞大量增殖。结论:该模型对探索鼠伤寒沙门氏菌引发肠炎的发病机制、病理生理、免疫等方面作用具有重要意义,并为特异性卵黄抗体被动免疫保护效果的后续评价奠定基础。

Kunming Mouse Model of Intestinal Infection Induced by Salmonella Typhimurium

Objective:To establish a model of intestinal infection induced by Salmonella Typhimurium using Kunming mouse.Methods:In order to improve the sensitivity of Salmonella Typhimurium, Kunming mice were given 5 g/L of streptomycin in drinking water for 2 days followed by 1 day without streptomycin. Animals were fasted 4 h before oral challenge with bacterial suspension. Mice were challenged intraperitoneally twice with Salmonella Typhimurium in different concentrations at 24 h of the experiment. Then the health condition of mice were observed. The pathological changes, ultrastructural changes and lymphocyte populations were examined by histopathology, transmission electron microscope and immunohistochemistry.Results:Mice that challenged with Salmonella Typhimurium showed typical clinical signs, including lethargy, inappetence, piloerection and even death. There was intestinal hyperemia swelling in dead mice. Histopathology indicated that the mice had epithelial damage and intestinal mucosal damage, severe submucosal edema and mononuclear inflammatory cells infiltrating in the lamina propria. In addition, transmission electron microscopy reveal that ultrastructure of intestine showed mitochondria vacuoles, eliminated crest and membrane fusion, expanded rough endoplasmic reticulum, and a lot of stick the original particles in goblet cell. Immunohistochemistry indicated that the lymph nodes were swollen and the number of T lymphocytes increased.Conclusion:The model was crucial for exploring the pathogenesis, pathophysiology and immunologic mechanism ininflammatory bowel disease induced by S.Typhimurium , and it will lay a foundation for evaluating the protective effects of specific egg yolk antibody.