目的 探讨Toll样受体在微小隐孢子虫感染致小鼠肠黏膜损伤中的作用机制.方法 30只雄性BALB/c小鼠随机分为正常对照组、感染1周组和感染2周组.用免疫抑制及卵囊灌胃的方法建立微小隐孢子虫肠道感染小鼠模型,感染1周组和2周组分别于感染后7 d和14 d剖杀,正常对照组于感染后14 d剖杀.光镜观察小鼠肠黏膜病理变化,并测量肠绒毛高度、隐窝深度及绒毛高度/隐窝深度比值;透射电镜观察小鼠肠黏膜超微结构;实时荧光定量PCR(qPCR)、Western blotting技术检测肠黏膜TLR2和TLR4表达情况.结果 光镜下,感染组小鼠肠绒毛水肿,明显萎缩变短,黏膜下层结构水肿,与肌层间形成间隙.与正常对照组比较,感染1周组和感染2周组小鼠空肠绒毛高度及绒毛高度/隐窝深度比值均明显降低(P均<0.05),隐窝深度明显升高(P均<0.01);且感染2周组小鼠空肠的绒毛高度及绒毛高度/隐窝深度比值均明显低于感染1周组(P均<0.05),隐窝深度明显高于感染1周组(P<0.01).透射电镜显示,感染组小鼠的空肠可见微小隐孢子虫卵囊,结构完整,卵囊周围的肠绒毛严重脱落,呈火山口状,卵囊壁与上皮细胞膜融合.qPCR结果显示,与正常对照组相比,感染1周组和感染2周组小鼠肠黏膜TLR2和TLR4 mRNA表达水平明显增高(P均<0.05);且感染2周组小鼠较感染1周组小鼠TLR2和TLR4 mRNA表达水平明显增高(P均<0.05).Western blotting检测结果表明,感染组小鼠肠黏膜TLR2和TLR4蛋白表达量较正常对照组显著增高(P均<0.05),且感染2周组小鼠TLR2和TLR4蛋白较感染1周组小鼠的表达量明显增高(P均<0.05).结论 TLR2和TLR4参与了肠黏膜对微小隐孢子虫的识别,感染导致的肠黏膜损伤可能与其上调TLR2和TLR4表达相关.“,”Objective To investigate the mechanism of Toll-like receptor in intestinal mucosal injury induced by Cryptospo-ridium parvum infection in mice.Methods Totally 30 male BALB/c mice were randomly divided into a normal control group,1-week infection group and 2-week infection group.The mice of the 1-week and 2-week infection groups were sacrificed 7 days and 14 days after the infection respectively,and the mice of the normal control group were sacrificed 14 days after the infection.The model of intestinal infection of C.parvum in mice was built by using the immunosuppressive method and oocyst intragastric ad-ministration.The pathological changes of the intestinal mucosa of mice were observed with a light microscope and the villus height,crypt depth and ratio of villus height/crypt depth were measured.The ultrastructure of the intestinal mucosa of mice was observed by a transmission electron microscope(TEM).The expressions of TLR2 and TLR4 in the intestinal mucosa were tested by qPCR and Western blotting.Results Under the light microscope,the intestinal villi were dropsical,obviously atrophied and shortened,and the submucosal structure was dropsical.The height of chorionic villi and the ratio of villus height to crypt depth in the jejunum of the 1-week and 2-week infection groups were significantly lower than those in the normal control group(all P<0.05),while the depth of the recess of the former two was significantly increased(all P<0.05).With the extension of the infection time,the villus height and the ratio of villus height to crypt depth in the jejunum of mice decreased significantly(both P<0.05),and the crypt depth increased significantly(P<0.01).The TEM observation showed that the structure of the oocyst of C.parvum in the jejunum of the infected mouse was intact,the villi around the oocyst were abscission seriously,and the oocyst wall was fused with the epithelial cell membrane.The qPCR observation showed that compared with the normal control group,the expressions of TLR2 mRNA and TLR4 mRNA in the intestinal mucosa of the 1-week and 2-week infection groups were significantly higher(all P<0.05).In addition,the expressions of TLR2 and TLR4 mRNA in the 2-week infection group were significantly higher than those in the 1-week infection group(both P<0.05).The Western blotting showed that the expres-sions of TLR2 protein and TLR4 protein in the intestinal mucosa of the 1-week and 2-week infection groups were significantly higher than those of the normal control group(all P<0.05).Furthermore,the expressions of TLR2 and TLR4 protein in the 2-week infection group were significantly higher than those in the 1-week infection group(both P<0.05).Conclusions TLR2 and TLR4 are important receptors for intestinal mucosal recognition of C.parvum.The C.parvum infection may lead to intestinal mucosal damage possibly via the mechanisms associated with the up-regulation of TLR2 and TLR4 expressions.