去甲肾上腺素诱导人巨噬细胞白细胞介素6表达及其机制

Norepinephrine induced expression of interleukin-6 in human macrophages and mechanisms

目的观察去甲肾上腺素(NE)预处理人单核/巨噬细胞U937细胞白细胞介素6(IL-6)的表达,探讨其致动脉粥样硬化可能的作用机制。方法 NE 0.01~10μmol·L^(-1)与U937细胞共培养24 h后,RT-PCR法检测细胞IL-6 mRNA水平;共培养6,9,12,24和48 h后,ELISA法检测细胞培养液上清中IL-6蛋白水平;共培养24 h后,荧光探针法检测细胞内活性氧(ROS)的生成。预先加入ROS抑制剂N-乙酰半胱氨酸(NAC)、NADPH氧化酶抑制剂二亚苯基碘(DPI)或线粒体复合物Ⅱ抑制剂噻吩甲酰三氟丙酮(TIFA)孵育1 h后,再加入NE 0.01~10μmol·L^(-1)继续培养24 h,ELISA法检测细胞培养液上清中IL-6蛋白水平。结果巨噬细胞IL-6 mRNA表达和蛋白水平随NE 0.01~10μmol·L^(-1)浓度增加和孵育时间延长而升高,NE 1.0μmol·L^(-1)刺激24 h,IL-6 mRNA表达和蛋白水平分别为细胞对照组的2.62和4.47倍(P<0.01);NE 0.01,0.1,1.0和10.0μmol·L^(-1)组ROS的生成分别为对照组的1.87,2.56,2.91和5.36倍(P<0.01)。NAC 10 mmol·L^(-1)和DPI 10μmol·L^(-1)均一定程度地抑制IL-6蛋白的表达(P<0.01),而TIFA无影响。结论 NE可诱导人巨噬细胞IL-6的表达,并可能通过NADPH氧化酶介导的ROS通路而促进炎症反应,促进动脉粥样硬化的发生和发展。

OBJECTIVE To investigate the effect of norepinephrine（NE） on expression of interleukin-6（IL-6） in human macrophages and explore its pro-inflammatory and pro-atherosclerotic mechanisms. METHODS Murine U937 macrophages were cultured and stimulated with 0.01-10 μmol·L-1of NE for 6, 9, 12, 24 and 48 h. The IL-6 mRNA level of 24 h was analyzed by RT-PCR, and IL-6 protein expression in the supernatant at 0, 6, 9, 12, 24 and 48 h was detected by ELISA. After 24 h, intracellular reactive oxygen species（ROS） generation was observed by DCF fluorescence. The cells were pretreated with antioxidant N-acetylcysteine（NAC）, complexⅡinhibitor thenoyltrifluoroacetone（TIFA） and NADPH oxidase inhibitor diphenyleneiodonium（DPI） for 1 h, and stimulated with different concentrations of NE for 24 h, before the level of IL-6 protein was detected by ELISA. RESULTS The expression of IL-6mRNA and protein increased with the concentration NE 0.01-10 μmol·L-1and incubation time. IL-6mRNA and protein levels in macrophages were 2.62 and 4.47-fold those in cell control group when treated with NE 1.0 μmol·L-1for 24 h. Meanwhile, as the concentration of NE increased, the generation of ROS was 1.87, 2.56, 2.91 and 5.36-fold that of cell control group（P〈0.01）. NAC 10 mmol·L-1and DPI 10 μmol·L-1significantly antagonized the effect of NE on IL-6 expression, but TIFA had no effect.CONCLUSION NE upregulates IL-6 expression, which may contribute to the formation and development of atherosclerosis via ROS mediated by NADPH oxidase in macrophages.