隐孢子虫感染小鼠淋巴细胞亚群及小肠超微结构的变化

The changes of ultrastructure of small intestine and lymphocyte subgroups in mice infected with Cryptosporidium

目的观察小鼠感染隐孢子虫后小肠粘膜超微结构的改变以及外周血淋巴细胞亚群的变化。方法用免疫抑制及卵囊灌胃的方法建立小鼠感染隐孢子虫病的模型。感染组小鼠分别在感染成功的第7、14和21d剖杀。同时设一正常对照组,各组小鼠每周剖杀一批,共3批。摘眼球取血,涂片,用免疫组化法检测外周血淋巴细胞及亚群。同时取近端空肠固定,作电镜切片,电镜下观察空肠超微结构的改变。结果免疫组化检测感染组小鼠外周血CD3+和CD4+T淋巴细胞数较正常对照组下降(P<0.01),而CD8+T淋巴细胞无显著变化(P>0.01),CD4+/CD8+细胞比值降低(P<0.01);电镜观察结果显示,感染隐孢子虫后小鼠近端空肠粘膜发生炎性病理变化,导致粘膜上皮细胞线粒体破坏。结论隐孢子虫感染与细胞免疫功能密切相关,T淋巴细胞尤其是CD4+淋巴细胞在抗隐孢子虫感染中起重要作用;隐孢子虫感染导致空肠粘膜炎性病变以及粘膜上皮细胞细胞器发生改变。

Objective To study the uhrastructural change in mucous membrane of small intestine and the peripheral blood lymphocyte of BALB/c mice infected with Cryptosporidium. Methods The mouse model was established hy immunity suppression and administering intragastrically with Cryptosiporidium oocyst. Mice were killed at days 7, 14 and 21, respectively, after the infection. Normal control given nothing was set upat the same time. The peripheral blood was collected for smearing preparation and detection of the peripheral blood lymphocyte and subgroup by immuno histo chemistry. And proximate jejunum was used for observation of ultrastructural change in mucous membrane of small intes tine using electron microscope. Results Compared with the normal group, the number of CD3^＋ and CD4^＋ lymphocyte was decreased （P〈0.01）, but CD8^＋ lymphocyte was not significantly decreased （P〈0.01）, while the ratio of CD4^＋ /CD8＋ （P〈0.01） was obviously reduced in the model group. Electron microscope showed that infection with Cryptosporidium induced inflammatory pathological change of intestinal mucosa membrane in proximate jejunum, and resulted in de struction of chondrosome in intestinal mucosa membrane epithelial cell. Conclusion Cryptosporidium infection is corre- lated variability with cellular immunity function. T lymphocyte, especially CD4^＋ lymphocyte plays important part in re sistance to Cryptosporidium infection, which can cause inflammatory pathological change of intestinal mucosa membrane in proximate jejunum and change of organelle in intestinal mucosa membrane epithelial cell.