基于“肠道菌群-SCFAs-GPRs”探讨青钱柳多糖对免疫抑制小鼠肠道黏膜免疫的调控作用及机制研究

多糖具有多种生物活性，引起了人们的广泛关注，但由于其不易被吸收，多糖口服后对肠黏膜免疫的影响机制还不明了。项目前期从青钱柳叶中分离得到青钱柳多糖，解析了结构，并初步发现其对肠道黏膜免疫具有调节活性，但其作用机制尚不清楚。本项目拟通过环磷酰胺诱导的免疫抑制小鼠构建肠道黏膜损伤模型，利用ELISA、RT-qPCR、蛋白免疫印迹、免疫组化等技术结合高通量测序与代谢组学方法，研究青钱柳多糖对肠道黏膜免疫功能分析免疫相关细胞因子、mRNA、蛋白；肠道菌群结构以及代谢产物短链脂肪酸（SCFAs）及相关信号转导通路等，分析多糖-肠道菌群结构-代谢产物SCFAs-细胞因子间的内在联系，阐明青钱柳多糖对免疫抑制小鼠肠道黏膜免疫调节作用的分子机制。研究成果将为青钱柳多糖的研究与开发提供理论依据，同时为其它生物活性多糖肠道健康的影响及其肠黏膜免疫的系统研究提供科学依据和理论基础。

Polysaccharides have attracted a lot of attention due to their significant bioactivities, however, it’s not easily absorbed after oral administration, and the mechanisms of polysaccharide on intestinal mucosal immunity are still unclear. In our previous study, polysaccharide fraction was isolated from of Cyclocarya paliurus, which structure was preliminarily determined. It has been found to exhibit regulatory effect on intestinal mucosal immunity, but its mechanism is still unclear. In this project, a model of intestinal mucosal damage will established by immunosuppressed mice induced by cyclophosphamide will be applied to assessment of intestinal mucosal immunoregulatory activity of this polysaccharides. The effects of Cyclocarya paliurus polysaccharide on the intestinal mucosal immunity associated factors such as cytokines, mRNA, proteins, etc. are studied through ELISA, RT-qPCR, western-blot and immunohistochemistry. The effects of polysacharide on intestinal mirobiota, and its metaboliteshort chain fatty acides (SCFAs) analyzed by high-throughput sequencing and metabolomics. Taking gut microbiota and metabolite SCFAs and related signal transduction pathways as pointcut, the phosphorylation and dephosphorylation of some key proteins signal transduction pathways will be investigated, and the intrinsic relationship of polysaccharide-intestinal mirobiota-short chain fatty acides (SCFAs)- immune indexs will be analyzed, to explore the mechanisms of regulatory effect on intestinal mucosal immunity of immunosuppressed mice. The results will provide a theoretical basis for the research and development of polysaccharides from Cyclocarya paliurus, as well as provide a scientific basis and theoretil basis for the intestinal health effects of other bioactive polysaccharides and the systemic study of intestinal mucosal immunity.