牛病毒性腹泻病毒（BVDV）能抑制IFN-Ⅰ和IFN-Ⅲ产生，引起持续性感染，造成重大损失。前期研究显示连翘酯苷A（FTA）体外能抑制BVDV复制，调节IFN-γ过度表达。本项目将以小鼠骨髓源的树突状细胞（BMDC）和Balb/c小鼠为模型，从体外和体内两个方面，进一步研究FTA抑制BVDV复制的作用机制。体外试验以BMDC为模型，通过BVDV处理和添加FTA，利用Western blot、RT-qPCR和siRNA等技术研究探索FTA通过JAK-STAT和负调节蛋白抑制BVDV复制的机制，筛选发挥主要调控作用的因子。体内试验使用BVDV和FTA单独及联合处理小鼠，通过病理分析、病毒中和和流式细胞术等技术手段，观察小鼠器官组织的病理变化、体液免疫和细胞免疫状况，阐明FTA保护小鼠抗BVDV感染的作用和机制，为FTA的应用和BVDV的防控提供理论依据。

BVDV can inhibit IFN-Ⅰ and IFN-Ⅲ，leading to persistent infection and great loss. Forsythiaside A (FTA) can inhibit BVDV replication and adjust the excessive expression of IFN-γ. The research will be carried out about the role and mechanism of inhibition of BVDV replication by forsythiaside with BMDCs in vitro and in vivo with the Balb/c mice. In vitro, the BMDCs will be exposed to BVDV and FTA. The mechanism of inhibition of BVDV replication by forsythiaside A via JAK-STAT and negative protein will be studied with Western blot, RT-qPCR and siRNA during BVDV infection. The key factors will also be screened. In vivo，the mice will be treated with BVDV and FTA. The pathological change, the condition of humoral immunity and cellular immunity of the mice will be observed with biopsy, viruses neutralization and flow cytometry. The research will clarify the mechanism of FTA inhibiting BVDV replication and provide theoretical basis for the application of FTA and BVDV prevention and control.