Toll样受体3（TLR3）在新孢子虫感染致孕鼠胚胎死亡过程中作用的研究

新孢子虫是引起牛流产的主要病原，但其致牛流产机制还不十分清楚。Toll样受体3（TLR3）是位于哺乳动物细胞上的模式识别受体。文献报道，孕鼠TLR3可被其配体双链RNA激活，诱导炎性细胞释放炎症细胞因子，促使胚胎死亡；在体外，新孢子虫也能激活细胞内TLR3。那么牛TLR3是否也参与了新孢子虫致孕牛流产的过程？目前未见相关报道。本项目拟以孕鼠作为模型，通过实时荧光定量PCR法和免疫组织化学法检测新孢子虫感染对孕鼠胎盘内TLR3表达量的影响；比较TLR3缺失孕鼠和正常孕鼠感染新孢子虫后胚胎死亡率的差异，并通过实时荧光定量PCR法检测TLR3对组织荷虫量及虫体分布的影响，通过流式细胞术检测TLR3对胎盘内某些炎性细胞数量的影响；阐明TLR3在新孢子虫感染致孕鼠胚胎死亡过程中的作用。该研究将为进一步揭示新孢子虫致牛流产机制提供新的思路和重要补充，为预防和控制牛新孢子虫病奠定基础。

Neospora caninum is recognized as a major cause of bovine abortion, but its pathogenesis is not completely understood. Toll like receptor 3 (TLR3) is an innate pattern recognition receptor in mammalian cells. Reports show that TLR3 of pregnant mouse can be activated by double stranded RNA, and induce the production of inflammatory cytokines and lead to fetal death; in vitro, N. caninum can activate TLR3 in cells. Then, whether TLR3 involves the bovine abortion caused by N. caninum? There is so far no relevant report. In this study, the expression of TLR3 in placenta of pregnant mouse model after infected by N. caninum was tested by real-time fluorescence quantitative PCR and immunohistochemistry; In the TLR3 gene knock out and TLR3 presence pregnant mouse model groups after infected by N. caninum, the fetal mortality, tissue parasite load and distribute tested by real-time fluorescence quantitative PCR and cytokine expressing cells tested by flow cytometry were compared; The role of TLR3 in fetal death of pregnant mouse model caused by N. caninum were elucidated. This study can provide new ideas and effective information for better understanding the mechanism of bovine abortion caused by N. caninum, foundation for the prevention and control of bovine neosporosis.