Effect of dexmedetomidine on lipopolysaccharides-induced release of cell cytokines from monocyte macrophage

Objective To explore the effect of dexmedetomidine(Dex) on the release of cell cytokines from monocyte macrophage RAW264.7 cells induced by lipopolysaccharide(LPS) and the expression of heme oxygenase(HO)-1. Methods RAW264.7 cells were cultured in six-well culture dishes with a density of 1×106/ml(2 ml/hole) and were randomly divided into 5 groups (n=6) by the number table method: normal control group(C group), Dex 10 μg/L(Dex group), LPS 1 mg/L(LPS group), LPS 1 mg/L+Dex 10 μg/L(LPS+Dex group), and ZnPPⅨ(inhibitor of HO-1), 10 μmol/L+ LPS 1 mg/L+Dex, 10 μg/L(ZnPPⅨ+LPS+Dex group). After incubation of 3, 6, 12, 24 h, ELISA was used to determine the concentrations of TNF-α, IL-6 and high mobility group box-1 protein(HMGB-1) in the supernatants of six wells in each group. Then, six wells in each group were chosen at incubation of 6 h and 12 h for determination of HO-1 expression by Western blot. Results Comparing with C group, the concentrations of TNF-α, IL-6 and HMGB-1 in the supernatants at 3, 6, 12, 24 h in the LPS group were significantly increased(P<0.05), and the expression of HO-1 at 6 h and 12 h time point was up-regulated in LPS group. Compared with LPS group, the concentrations of TNF-α, IL-6 and HMGB-1 in LPS+Dex group were attenuated(P<0.05). Meanwhile, the expression of HO-1 at 6 h and 12 h time point was up-regulated in LPS+Dex group. Compared with LPS+Dex group, the concentrations of TNF-α, IL-6 and HMGB-1 in ZnPPⅨ+LPS+Dex group were increased(P<0.05). However, the expression of HO-1 was reduced in ZnPPⅨ+LPS+Dex group(P<0.05). Conclusions Dex could inhibit the release of cell cytokines from RAW264.7 via up-regulating the levels of HO-1 expression. Key words: Dexmedetomidine; Inflammatory cytokines; Lipopolysaccharide; Heme oxygenase-1