谷维素抑制DSS诱导的小鼠结肠炎症及其分子机理研究

Molecular Mechanism Underlying the Amelioration of Dextran Sulphate Sodium (DSS)-induced Colitis in Mice by Oryzanol

摘要:

谷维素（oryzanol）是米糠中重要的活性物质之一。C57BL/6小鼠连续饮用1.0%葡聚糖硫酸钠（dextran sulphate sodium, DSS）12 d，用以建立溃疡性结肠炎模型，评估谷维素的抗炎作用及其分子机理研究。结果发现：谷维素组小鼠能明显缓解DSS诱导的结肠炎症，小鼠肠壁厚度、结肠长度、结肠重量、炎症细胞浸润、疾病活动指数（disease active index, DAI）等病理指标明显改变；谷维素也能明显改善结肠组织中炎症损伤重要生化指标如髓过氧化物酶（myeloperoxidase，MPO）和丙二醛（malondialdehyde, MDA）的含量，同时减少血浆中亚硝酸盐的含量；RT-qPCR技术分析发现结肠组织炎症因子TNF-α、IFN-γ、IL-1和IL-6等mRNA表达水平受到明显抑制，Western blotting分析进一步证实了谷维素能抑制炎症因子的蛋白表达水平。结论：谷维素对DSS诱导的小鼠结肠炎具有抑制作用，其作用的分子机理可能与下调炎症因子的表达相关。

Abstract:

Oryzanol is one of the important active substances in rice bran. A mouse model of ulcerative colitis was established by feeding C57BL/6 mice continuously with 1.0% sulphate sodium D (DSS), and the anti-inflammatory effect of oryzanol and its molecular mechanism were evaluated. The results showed that the symptoms of DSS-induced colitis in the mice from oryzanol group were significantly alleviated. The thickness of bowel wall, colon length, colon weight, inflammatory cell infiltration, disease activity index (DAI) and other important pathological indicators were improved significantly. Oryzanol could also significantly improve important biochemical indicators of inflammatory injury in colonic tissues, such as myeloperoxidase (MPO) and malondialdehyde (MDA) contents, and reduce the plasma nitrite content. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis found that the mRNA expression levels of inflammatory factors, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-1, and IL-6 were significantly reduced in colonic tissues. Western blotting further confirmed that oryzanol suppressed the protein expression of inflammatory factors in colonic tissues. It was concluded that oryzanol had an inhibitory effect on DSS-induced colitis in mice and its molecular mechanism may involve the down-regulation of the expression of inflammatory factors.