Inhibition of IL-6 and IL-8 production in LPS-stimulated human gingival fibroblasts by glycyrrhizin via activating LXRα

The aim of this study was to clarify the anti-inflammatory effects and its molecular mechanism of glycyrrhizin on LPS-stimulated human gingival fibroblasts (HGFs), which will be of benefit for periodontitis treatment. An MTT assay was performed to assess the effects of glycyrrhizin on cellular viability. The levels of IL-6 and IL-8 were measured by ELISA. The expression of iNOS, COX-2, NF-kappa B, and LXR alpha were detected by western blot analysis. The results showed that glycyrrhizin significantly inhibited LPS-induced IL-6 and IL-8 production, as well as COX-2 and iNOS expression. LPS-induced NF-kappa B activation in HGFs was also inhibited by treatment of glycyrrhizin. Furthermore, glycyrrhizin increased the expression of LXR alpha in a concentration-dependent manner. In addition, the inhibition of glycyrrhizin on IL-6 and IL-8 production was reversed by LXR alpha inhibitor GGPP. In conclusion, these results indicated that glycyrrhizin exhibited its anti-inflammatory effects in HGFs by activating LXR alpha. (C) 2017 Elsevier Ltd. All rights reserved.