基于FXR的补骨脂对溃疡性结肠炎肠粘膜屏障的保护作用及机制研究

Ulcerative colitis (UC) is a recurrent, chronic and nonspecific intestinal inflammation.It is a refractory and common disease of digestive system. Intestinal mucosal barrier injury is the main pathologic process in UC. Persistent damage of intestinal mucosal barrier is closely related to the recurrence of UC. The Farnesoid X Receptor (FXR) is a kind of bile acid activation of nuclear receptors, plays an important role in maintain bile acids metabolism and the intestinal mucosal functions and integrity. Psoralen is one of the traditional Chinese medicine which is widely used in the spleen and kidney deficiency type of UC which has a good clinical effect. We previously found that Psoralen significantly increased intestinal FXR expression, and had beneficial effect on the injury in intestinal mucosal barrier. On the basis of the early study, our study will foucs on the bile acids metabolism and the integrality of gut barrier by RNA interference, RT-PCR and Western blot based on the regulation of FXR of Psoralen and its main active ingredients, to clarify the molecular mechanism of protective effect of Intestinal mucosal barrier injury at the whole body, cellular and molecular levels. This study will provide a scientific basis for the treatment of UC, it also provide experimental basis for further development and use of Psoralen.

溃疡性结肠炎是一种病因不明、反复发作的慢性非特异性结肠炎症，为消化系统疾病中常见的难治性疾病。溃疡性结肠炎的发病及复发与肠黏膜屏障的持续性损害密切相关。法尼酯衍生物X受体（FXR）是一种胆汁酸激活的核受体，在维持胆汁酸稳态及肠粘膜屏障完整性等方面起到了重要的作用。补骨脂是治疗脾肾两虚型慢性溃疡性结肠炎的常用中药，临床效果良好。前期研究表明补骨脂能明显上调肠道FXR的表达，对溃疡性结肠炎小鼠肠粘膜屏障损伤具有一定的保护作用。本项目拟在前期研究基础上，通过RNA干扰、RT-PCR和Western blot等技术，从FXR介导的肠道紧密连接蛋白调控角度阐释补骨脂及其活性成分对溃疡性结肠炎肠粘膜屏障的保护作用和分子机制，为补骨脂及其单体进一步开发和临床应用提供实验依据。

溃疡性结肠炎是一种病因不明、反复发作的慢性非特异性结肠炎症，为消化系统疾病中常见的难治性疾病。溃疡性结肠炎的发病及复发与肠黏膜屏障的持续性损害密切相关。法尼酯衍生物X受体（FXR）是一种胆汁酸激活的核受体，在维持胆汁酸稳态及肠粘膜屏障完整性等方面起到了重要的作用。补骨脂是治疗脾肾两虚型慢性溃疡性结肠炎的常用中药，临床效果良好。前期研究表明补骨脂能明显上调肠道FXR的表达，对溃疡性结肠炎小鼠肠粘膜屏障损伤具有一定的保护作用。本项目在前期研究基础上，通过RNA干扰、RT-PCR和Western blot等技术，从FXR介导的肠道紧密连接蛋白调控角度阐释补骨脂及其活性成分对溃疡性结肠炎肠粘膜屏障的保护作用和分子机制。研究结果表明，补骨脂水提物和补骨脂素可以显著降低DSS致小鼠UC模型的体重下降和结直肠的缩短，延缓并减轻了小鼠的腹泻和便血情况，降低小鼠的死亡率和小鼠血清细胞因子升高，显著降低DSS导致的隐窝萎缩和炎性细胞浸润，显著升高UC小鼠模型血清总胆汁酸水平和降低结肠内容物总胆汁酸水平。补骨脂素可以上调DSS致小鼠UC模型回肠组织Fxr、Shp和Fgf15 mRNA转录以及FXR和FGF15蛋白表达，上调回肠组织Asbt、Ostα/β和I-Babp mRNA的表达。体外研究结果表明，补骨脂素可明显上调FXR基因沉默前FXR、SHP及通透蛋白claudin-1、occludin和ZO-1的表达。本项目从体内、体外两个方面开展研究，阐明补骨脂可通过上调肠道FXR的表达，减少结肠内胆汁酸含量同时通过调节肠道紧密连接蛋白而发挥肠黏膜屏障的保护作用，此研究结果为补骨脂及其单体进一步开发和临床应用提供实验依据。