1,25(OH)_2D_3通过调控连接蛋白的表达缓解DSS诱导的小鼠结肠炎

1,25(OH)_2D_3 alleviate DSS-induced acute colitis via regulating tight junction proteins

目的:利用葡聚糖硫酸钠(dextran sulfate sodium,DSS)诱导的急性结肠炎小鼠模型探讨活性维生素D[1,25(OH)_2D_3]缓解结肠炎的作用及机制。方法:利用DSS诱导小鼠急性结肠炎,分析炎症表型,检测杯状细胞变化情况及肠道通透性的改变,通过实时荧光定量聚合酶链式反应(real-time quantitative PCR,RT-qPCR)、免疫蛋白印迹试验(Western blot,WB)及免疫荧光分析各组小鼠结肠组织连接蛋白的表达差异。利用Ca CO-2单层细胞模型,检测1,25(OH)_2D_3对连接蛋白的保护作用。通过染色质免疫共沉淀、荧光素酶报告基因实验探讨1,25(OH)_2D_3调控Claudin 4表达的机制。结果:1,25(OH)_2D_3可明显缓解DSS诱导的结肠炎症,其可能通过增加连接蛋白表达,维持杯状细胞结构,提高肠道上皮屏障作用,减轻肠道通透性,进而减少炎症反应发挥保护作用。结论:1,25(OH)_2D_3可在小鼠急性结肠炎中发挥抗炎作用,维持肠道通透性稳定,增强细胞连接蛋白的表达水平,并且通过维生素D受体转录调控Claudin 4的表达。

Objective：To investigate the effects and mechanisms of 1,25（OH）2D3 on ameliorating dextran sulfate sodium（DSS）-induced colitis in mice. Methods：With DSS-induced colitis mice model established,inflammatory phenotype and goblet cells were detected and analyzed among model groups.The expression levels of tight junction proteins（TJs）among colonic tissues from different model groups were detected by RT-q PCR,Western blot and immunofluorescence staining. Using Caco-2 monolayer cell model,the protection of 1,25（OH）2D3 for TJs was detected in vitro. The mechanism of 1,25（OH）2D3 regulating expression of Claudin 4 was investigated via Chromatin immuno-precipitation（Ch IP）and luciferase reporter assay. Results：1,25（OH）2D3 could enhance the intestinal epithelial barrier by promoting the expression of TJs,maintaining the structure of goblet cells and decreasing the intestinal permeability,thus relieving inflammation in DSS-induced acute colitis in mice. Conclusion：1,25（OH）2D3 plays a protective role in acute colitis mouse model via preserving intestinal permeability,promoting the expression levels of TJs and regulating the expression of Claudin4 through Vitamin Dreceptor.