枸杞多糖调控CD4+T细胞分化治疗溃疡性结肠炎的机制研究

Ulcerative colitis (UC) is a complex inflammatory process in which various immune cells are activated. It has been proven that drug intervention against any single individual molecule involved in the complicated pathological processes of UC is difficult and is not feasible to effectively reverse the development of inflammation. Studies have shown that Lyciumbar Barum Polysaccharides (LBP) can activate a variety of immune cells and regulate the immune balance at different stages of inflammation. Bearing the information stated above in our mind, we would like to test the therapeutic effects of LBP on UC. In order to answer this question, we have conducted a series of preliminary studies. Our studies showed that LBP significantly inhibits DSS-induced colitis. However, the mechanisms by which LBP protects the colon from DSS-induced injury are still largely unknown. The crucial pathogenesis of UC is now considered to be an imbalance of CD4+ T cell differentiation. It is suggestted that LBP may regulate the immune system of UC-related inflammation via modulating differentiation of CD4+ T cell. Therefore, the specific aim of our current study is to further deeply understand and delineate the LBP's therapeutic mechanisms for alleviating UC-induced inflammation by using DSS-induced mouse chronic colitis. We are going to conduct in vivo and vitro experiments to check the effect of LBP on major biological behaviors related to CD4+T cells, including cell number, cell activity, differentiation, and secretion of inflammatory cytokines. It should be emphasized that we will investigate the role of LBP on differentiation of CD4 + T cell in a more detail way. In addition, in order to explore the specific downstream signaling pathways elicited or(and) modulated by LBP, we will use the state-of-the-art microarray techniques to screen the upstream and downstream target genes involved in regulation of activation of Th1/Th17/Th2 cells. Based on these work, we expect that we will further confirm the benefits of LBP for management of UC, shed the light on the possible molecular mechanisms behind these observations, and lay the foundation for developing our LBP as a possible new therapeutic strategy for UC treatment.

溃疡性结肠炎(UC) 是多种免疫细胞被激活的复杂炎症过程，单独针对任何单一分子的药物干预都难以有效逆转炎症的发生发展，研究证实枸杞多糖可在炎症不同阶段激活多种免疫细胞调控免疫平衡。前期工作发现：枸杞多糖可改善DSS诱导的急性肠炎，但其治疗作用仍需完善。目前认为UC发病机制的关键是CD4+Ｔ细胞分化失衡，因此推测枸杞多糖可能通过调节CD4+T细胞分化进而对UC的炎症反应起到免疫调控作用。本研究拟制备DSS慢性结肠炎小鼠模型明确枸杞多糖对UC的治疗效果；借助体内、外试验研究枸杞多糖对CD4+T细胞数量、活性、分化、炎性因子分泌的影响，探讨枸杞多糖对CD4+T细胞分化的调控作用；应用基因芯片筛选 Th1/Th17/Th2细胞上调/下调的靶基因，探讨枸杞多糖调控CD4+Ｔ细胞分化的下游信号通路。以期揭示枸杞多糖治疗UC的可能机制，为开发应用枸杞多糖，研发UC的治疗药物奠定实验基础。

溃疡性结肠炎(UC)是多种免疫细胞被激活的复杂炎症过程，单独针对任何单一分子的药物干预都难以有效逆转炎症的发生发展，研究证实枸杞多糖可在炎症不同阶段激活多种免疫细胞调控免疫平衡。我们的研究发现：1，枸杞多糖可改善DSS诱导的急性肠炎，通过制备 DSS慢性结肠炎小鼠模型发现：枸杞多糖治疗后，相较于DSS组，小鼠的体重升高（P＜0.05），DAI评分降低（P＜0.05），结肠大体形态有所改善，结肠长度增长（P＜0.05），相较于DSS组的肠黏膜变薄、结构破坏明显，肠壁各层均可见不同程度炎症细胞浸润，部分区域肠黏膜缺损，枸杞多糖治疗组的肠黏膜厚度有所增加、结构较为完整，MPO活性下降（P＜0.05），表明枸杞多糖能够抑制慢性溃疡性结肠炎的肠道症状和部分炎症反应。2，借助体内、外试验研究枸杞多糖对CD4+T 细胞亚型细胞的数量及相关炎性因子分泌的影响，发现：相较于DSS组，枸杞多糖治疗后慢性溃疡性结肠炎模型鼠外周血中Th1、Th2、Treg的细胞数量减少（P＜0.05），Th17的变化无统计学意义（P＞0.05）；结肠组织中Th1、Th2、Th17、Treg均减少（P＜0.05），TNF-α和IFN-γ因子mRNA的表达量减少（P＜0.05），T-βmRNA的表达量无明显变化，结肠组织匀浆液中TNF-α、IFN-γ和T-β因子浓度降低（P＜0.05）；3，枸杞多糖刺激后，溃疡性结肠炎缓解期和活动期的患者外周血内CD4+T细胞的分化亚型有变化，相较于枸杞多糖刺激前，枸杞多糖刺激后Th1、Th17、Treg的细胞数量减少，Th2的细胞数量增加（P＜0.05），表明枸杞多糖能够调节CD4+ T细胞向Th1/Th2/Th17/Treg细胞亚型的分化及相关炎性因子的分泌，进而调节UC的炎症反应，改善UC炎症反应造成的组织损伤，为开发应用枸杞多糖，研发 UC 的治疗药物奠定实验基础。