趋化因子受体CCR2、CCR5及其配体巨噬细胞炎性蛋白-1α在小鼠克罗恩病模型中表达的研究

Expression of Chemokine Receptors CCR2, CCR5 and Macrophage Inflammatory Protein-1α in Crohn’s Disease Mouse Model

背景:趋化因子受体及其配体是白细胞聚集的关键因素,可介导淋巴细胞聚集到正常的小肠。目的:研究趋化因子受体CCR2、CCR5及其配体巨噬细胞炎性蛋白(MIP)-1α在小鼠克罗恩病(CD)肠黏膜固有层单个核细胞(LPMC)中的表达,探讨炎症性肠病(IBD)发生、发展的分子机制。方法:健康雄性BALB/c小鼠20只,随机分为对照组和模型组。模型组小鼠以三硝基苯磺酸(TNBS)灌肠造模。5d后处死,提取和培养LPMC,采用流式细胞仪测定小鼠LPMC中趋化因子受体CCR2、CCR5的表达;采用酶联免疫吸附测定(ELISA)检测培养上清液中MIP-1α的分泌;采用逆转录聚合酶链反应(RT-PCR)检测MIP-1α mRNA的表达。结果:小鼠CD模型组LPMC中CCR2、CCR5阳性CD4+细胞比例显著高于对照组(P<0.05);LPMC原代培养后,模型组上清液MIP-1α的分泌显著高于对照组(P<0.05);模型组MIP-1α mRNA的表达显著高于对照组(P<0.05)。结论:趋化因子受体CCR2、CCR5及其配体MIP-1α在小鼠CD的LPMC中表达增高,可能参与了CD的免疫应答和炎症反应。

Background： Chemokine receptors and their ligands play a key role in the recruitment of leucocytes and can mediate the recruitment of lymphocytes to normal small intestine. Aims： To determine the expression of chemokine receptors CCR2, CCR5 and their ligand macrophage inflammatory protein （MIP）-1α in the colonic lamina propria mononuclear cells （LPMC） of mouse with induced colitis and to explore the molecular mechanism of the development of inflammatory bowel disease （IBD）. Methods： Twenty healthy male BALB/c mice were divided into two groups, model group and normal control group. Crohn＇s disease was induced by trinitrobenzene sulfonic acid （TNBS） in the model group. The mice were sacrificed 5 days afterwards and LPMC were isolated and cultured. The expression of CCR2 and CCR5 on LPMC were determined by flow cytometry. The secretion of MIP-1α in the supernatant was determined by enzyme-linked immunosorbent assay （ELISA）, and the expression of MIP-1α mRNA was determined by reverse transcriptase polymerase chain reaction （RT-PCR）. Results： The ratio of CCR2- and CCR5-positive CD4^＋ cells in LPMC was significantly higher in the model group than that in the normal control group （P〈0.05）. The secretion of MIP-1α in the supernatant of primary culture of LPMC was significantly higher in the model group than that in the normal control group （P〈0.05）. The expression of MIP-1α mRNA was also significantly higher in the model group than that in the normal control group （P〈0.05）. Conclusions： Expression of chemokine receptors CCR2 and CCR5 and their ligand MIP-1α increase significantly in LPMC of mouse model with Crohn＇s disease, and it may be involved in the immune response and inflammatory reaction of Crohn＇s disease.