5-脂氧合酶在小鼠恶唑酮溃疡性结肠炎中的表达研究

Expression of 5-lipoxygenase mRNA and protein in colon mucosa of mice with oxazolone-induced ulcerative colitis

目的研究5-脂氧合酶（5-LOX）在恶唑酮诱导溃疡性结肠炎（UC）小鼠结肠黏膜中的表达情况，探讨其在UC发病机制中的作用及其与炎症程度的关系。方法50只Balb／c小鼠分为正常对照组10只和模型组40只。模型组用3％恶唑酮致敏2d，第5天用0．5％恶唑酮灌肠。第8天用颈椎脱臼法处死所有小鼠。实验期间观察小鼠疾病活动指数（DAI），处死小鼠后行结肠组织学病理评分（HPS）。RT—PCR法检测结肠黏膜5-LOXmRNA的表达，免疫组织化学方法检测结肠黏膜5-LOX的蛋白表达情况。结果模型组DAI和HPS均高于对照组，5-LOXmRNA和蛋白表达也明显高于对照组（均P〈001），并随炎症程度加重。表达水平明显增高。结论5-LOX在UC中表达水平明显升高，并参与了UC的发生和发展，在一定程度上可反应疾病的活动度，并且可能作为药物治疗的潜在靶点。

Objective To investigate the expression of 5-1ipoxygenase （5-LOX） mRNA in colon mucosa in mice with oxazolone-induced ulcerative colitis （UC）. Methods Fifty female Balb/c mice were divided into control group （n=10） and UC group （n=40）. Mice in UC group received subcutaneous injection of 3% （w/v） oxazolone for 2d and subsequently received enema with 0.5%（w/v） oxazolone on d5 after sensitization. On d7 the mice were sacrificed for harvest of colon samples; disease activity index （DAI） and histopathological score （HPS） were also evaluated. The expression of 5-LOX mRNA and protein in colon mucosa were detected by RT-PCR and immunohistochemistry, respectively. Results The DAI and HPS were higher in UC group than those in control group. The expression of 5-LOX mRNA and protein were significantly increased in UC mice compared to controls （P〈0.01）, and the expression was positively correlated with the severity of colonic inflammation. Conclusion The expression of 5-LOX is up-regulated in colon mucosa of mice with oxazolone-induced ulcerative colitis, which indicates that 5-LOX may be involved in the development of UC and 5-LOX might be a potential pharmacological target for treatment of UC.