Norepinephrine induced expression of interleukin-6 in human macrophages and mechanisms / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To investigate the effect of norepinephrine (NE) on expression of interleu?kin-6 (IL-6) in human macrophages and explore its pro-inflammatory and pro-atherosclerotic mecha?nisms. METHODS Murine U937 macrophages were cultured and stimulated with 0.01-10μmol·L-1 of 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-6 mRNA and protein increased with the concentration NE 0.01-10 μmol · L-1 and incubation time. IL-6 mRNA and protein levels in macrophages were 2.62 and 4.47-fold those in cell control group when treated with NE 1.0μmol·L-1 for 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-1 and DPI 10 μmol · L-1 significantly 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 develop?ment of atherosclerosis via ROS mediated by NADPH oxidase in macrophages.