核受体与溃疡性结肠炎大鼠疾病转归的相关性研究

Study on Correlation Between Nuclear Receptors and Outcome of Rats with Ulcerative Colitis

关键词:  溃疡性结肠炎  核受体  炎症因子  转归

Key words:  ulcerative colitis  nuclear receptor  inflammatory factor  outcome

摘要:

目的 研究大鼠结肠组织中相关核受体的表达与溃疡性结肠炎（ulcerative colitis，UC）大鼠疾病转归的相关性。方法 SD大鼠一次性结肠灌注2，4，6-三硝基苯磺酸（2，4，6-trinitrobenzene sulfonic acid，TNBS）造模，诱导UC急性期和UC炎症消退后恢复期，收集大鼠血浆和结肠组织。计算疾病活动指数、粪便含水率，考察结肠病理变化，评估大鼠UC模型是否成功；ELISA测定血浆肿瘤坏死因子-α（tumor necrosis factor，TNF-α），γ干扰素（interferon-γ，IFN-γ），白细胞介素4（interleukin 4，IL-4）和IL-13的含量；比色法检测结肠髓过氧化物酶（myeloperoxidase，MPO）活性；Real-time PCR测定法尼醇X受体（farnesoid X receptor，FXR）、孕烷X受体（pregnane X receptor，PXR）、组成型雄甾烷受体（constitutive androstane receptor，CAR）、过氧化物酶体增殖物激活受体γ（peroxisome proliferators activate receptor g，PPAR γ）mRNA的表达；R软件评估核受体与炎症因子之间的相关性。结果 模型组大鼠疾病活动指数和粪便含水率均明显下降，提示UC大鼠模型建立成功。与正常对照组相比，急性炎症期组大鼠结肠FXR、CAR、PPARγ mRNA表达水平明显下降，血浆TNF-α和IFN-γ含量呈显著负相关升高（P<0.05），FXR与IL-4显著正相关（P<0.05）；结肠PXR表达水平降低，与炎症因子无相关性；此外，大鼠血浆MPO含量升高，与PPARg呈显著负相关（P<0.05）。与急性炎症期组相比，炎症消退后恢复期组大鼠血浆促炎因子TNF-α、IFN-γ含量及血浆MPO活性显著降低（P<0.05），而血浆抑炎因子IL-4与IL-13含量显著升高（P<0.05），结肠FXR、PXR、CAR、PPARγ mRNA表达水平则明显升高（P<0.05）。结论 UC大鼠结肠组织核受体FXR、CAR、PPARγ水平与UC大鼠的发病及转归具有相关性。

Abstract:

OBJECTIVE To investigate the correlation between the expression of related nuclear receptors in colonic tissues and the outcome of rats with ulcerative colitis(UC). METHODS Serum and colon tissues were collected from SD rats druing UC acute stage and UC recovery stage which were induced by one-time colon perfusion of 2,4,6-trinitrobenzene sulfonic acid(TNBS). Disease activity index and fecal water content were calculated to investigate the pathological changes of the colon, so as to evaluate the rat UC model. Plasma tumor necrosis factor(TNF-a), interferon-g(IFN-g), interleukin 4(IL-4) and IL-13 were determined by ELISA. Colorimetric method was used to detect the activity of colonic myeloperoxidase(MPO). Real-time PCR was used to determine the mRNA expression of farnesoid X receptor(FXR), pregnane X receptor(PXR), constitutive androstane receptor(CAR), peroxisome proliferators activate receptor g(PPARg). R software assessed the correlation between nuclear receptors and inflammatory factors. RESULTS The disease activity index and fecal water content of rats in the model group decreased significantly, indicating the success establishment of UC rat model. Compared with the normal control group, the mRNA expression levels of FXR, CAR and PPARg in the colon of rats in the acute stage of UC group were significantly decreased, while the contents of plasma TNF-a and IFN-g were significantly negatively correlated with them(P<0.05), IL-4 was significantly positively correlated with FXR; colonic PXR expression level was decreased, which was not correlated with inflammatory factors; in addition, the plasma MPO content in rats increased, which was negatively correlated with PPARg(P<0.05). Compared with the acute inflammatory stage of UC group, the levels of plasma proinflammatory factors TNF-a, IFN-g, and plasma MPO activity were significantly decreased in the recovery stage of UC group(P<0.05), while the levels of plasma anti-inflammatory factors IL-4 and IL-13 were significantly increased(P<0.05), and the mRNA expression levels of colon FXR, PXR, CAR, and PPAR were significantly increased(P<0.05). CONCLUSION The colonic nuclear receptors FXR, CAR and PPAR in UC rats are correlated with the outcome of UC rats.