1,25-(OH)_2D_3通过NF-κB通路对小鼠溃疡性结肠炎的影响

EFFECTS OF 1,25-(OH)_2D_3 ON ULCERATIVE COLITIS IN MICE THROUGH REGULATING NF-κB PATHWAY

目的研究1,25-(OH)2D3对小鼠溃疡性结肠炎中核转录因子κB(nulear factor-κB,NF-κB)家族的影响,探讨其在小鼠溃疡性结肠炎中的作用。方法 6w龄雌性C57BL/6小鼠36只,随机分为正常对照组,溃疡性结肠炎模型组,1,25-(OH)2D3低、高剂量干预4组,除对照组外其余三组分别用葡聚糖硫酸钠(DSS)对小鼠进行溃疡性结肠炎造模,9d后处死小鼠,取血清和结肠组织。根据小鼠一般情况进行疾病活动指数(disease activity index,DAI)评分,观察小鼠结肠大体形态和病理学损伤情况,对其进行组织病理学评分。酶联免疫吸附法(ELISA)法检测小鼠血清TNF-α、IL-6含量,免疫组化测定结肠组织磷酸化IκB激酶β(phosphorylated inhibitor of nuclear factor kappa-B kinaseβ,p-IKKβ)、磷酸化核转录因子κB抑制蛋白α(phosphorylated inhibitor of NF-κB,p-IκB)、NF-κBp65蛋白表达情况。结果与DSS模型组比较,1,25-(OH)2D3干预组结肠组织IKKβ磷酸化减少,IκBα降解明显降低,NF-κB活化减少,小鼠血清TNF-α、IL-6含量下降,小鼠溃疡性结肠炎大体形态改善,组织学损伤较轻。结论 1,25-(OH)2D3可以通过抑制NF-κB通路,对小鼠溃疡性结肠炎起保护作用。

Objective To explore the effects of 1,25-（OH）2D3 on nuclear factor-κB（NF-κB） family in mice with ulcerative colitis.Method Thirty-six 6-week-old C57BL/6 female mice were randomly divided into four groups, including normal control group （control）,ulcerative colitis model group （model）,10ng 1,25-（OH）2D3 group and 100ng 1,25-（OH）2D3 group. The model was induced by dextran sulfate sodium（DSS）. The mice in 1,25-（OH）2D3 groups were administered with 1,25-（OH）2D3 intragastrically per day , while the mice in the other two groups were given with an equal volume of PBS buffer solution. Nine days later, all the mice were sacrificed. The serum and colon samples were collected. The gross and histological score of colon, and disease activity index（DAI） were evaluated, Serum levels of TNF-α and IL-6 were measured by enzyme-liked immunosorbent assay （ELISA）,and the protein expression of phosphorylated inhibitor of nuclear factor kappa-B kinaseβ（p- IKK）β,phosphoryated inhibitor of NF-κB （p-IκB） and NF-κBp65 in colonic tissues were measured by immunohistochemistry.Results The expression of p-IKKβ,p-IκBα and NF-κBp65 in colonic tissues were downregulated in 1,25-（OH）2D3 groups than those in the model group,while the serum levels of TNF-α and IL-6 were also reduced. Furthermore, The DAI and histological damage were significantly improved in the 1,25-（OH）2D3 groups. Conclusion 1,25-（OH）2D3 has protective effects on ulcerative colitis through regulating the NF-κB signaling pathways.