摘要
背景:正常肠上皮作为物理屏障能限制肠道微生物的入侵。肠上皮细胞极低表达Toll样受体(TLR)4和髓样分化蛋白(MD)-2,不与脂多糖(LPS)反应。目的:探讨以细胞因子肿瘤坏死因子(TNF)-α、白细胞介素(IL)-1β、干扰素(IFN)-γ和LPS刺激人结肠癌细胞系HT-29后,TLR4和MD-2的表达及其对LPS反应性的变化。方法:将HT-29细胞分为8组,分别加入RPMI1640、TNF-α、IL-1β、IFN-γ、LPS、TNF-α+LPS、IL-1β+LPS、IFN-γ+LPS干预;酶联免疫吸附测定(ELISA)检测各组细胞上清液内IL-8水平;逆转录聚合酶链反应(RT-PCR)检测各组细胞TLR4和MD-2mRNA的表达。结果:TNF-α、IL-1β和IFN-γ能显著上调HT-29细胞TLR4、MD-2mRNA和IL-8的表达(P<0.01);HT-29细胞与TNF-α、IL-1β、IFN-γ预孵育后再以LPS刺激,IL-8的表达进一步上调(P<0.01)。结论:细胞因子(TNF-α,IL-1β,IFN-γ)可增加肠上皮细胞TLR4和MD-2的表达,促进其对LPS的反应,引起肠上皮细胞对常驻菌的过度反应,从而启动或加重肠道炎症。
Background： Normal intestinal epithelium serves as physical barrier to limit access of enteric microbes. Intestinal epithelial ceils （IEC）, which express low levels of toll-like receptor （TLR） 4 and myeloid differential protein （MD）-2, lipopolysaccharide （LPS）-non-responsive. Aims： In this study human colonic cancer ceil line HT-29 stimulated by cytokines, such as tumor necrosis factor （TNF）-α, interleukin （IL）-β, interferon （IFN）-γ and LPS to appraise their effects on the expression of TLR4, MD-2 and responsiveness to LPS. Methods： HT-29 ceils were divided into 8 groups and were treated with RPMI 1640, TNF-α, IL-β, IFN-γ LPS, TNF-α＋LPS, IL-β＋LPS and IFN-γ＋LPS, respectively. Supernatants were harvested to measure IL-8 by enzyme-linked immunosorbent assay （ELISA）. The expression of TLR4, MD-2 mRNA were assayed by reverse transcriptase polymerase chain reaction （RT-PCR）. Results： TNF-α, IL-β, IFN-γincreased significantly the TLR4 and MD-2 mRNA expression and IL-8 production in HT-29 ceils （P〈0.01）. Pre-incubation of HT-29 ceils with TNF-α, IL-β, IFN-γ followed by LPS stimulation augmented the production of IL-8 secretion （P〈0.01）. Conclusions： Cytokines （TNF-α, IL-β, IFN-γ） enhance TLR4, MD-2 expression and promote the reaction with LPS, leading to overactivity of IEC with commensal bacteria, and accordingly initiate or perpetuate the intestinal inflammation.
出处
《胃肠病学》
2007年第2期88-91,共4页
Chinese Journal of Gastroenterology
