Inhibitory Effects And Mechanism Of Dihydroartemisinin On LPS-induced Inflammatory Response On BV-2 Microglial Cells

Objective:To investigate the inhibitory effects of Dihydroartemisinin(DHA)on LPS-induced BV-2 microglia activation and the release of pro-inflammatory mediators in neuroinflammatory response,and to explore the underlying mechanism.Methods:Inflammatory model was established by exposure of BV-2 cells to LPS for 24 h in vitro.BV-2 microglia cells were treated with different concentrations of DHA(0.5、1、2、4 μmol/L)and cell viability was tested by CCK8 assay.A harmless concentration(1μmol/L)of DHA was used for intervention on the follow-up inflammatory model.The change of morphology of BV-2 cells was observed by inverted phase contrast microscope.The expression of inflammatory cytokines(IL-1β,IL-6,TNF-α)and iNOS were measured by RT-PCR.The levels of interleukin-1 beta(IL-1β),tumor necrosis factor-alpha(TNF-α),and interleukin-6(IL-6)released from microglia cells in the culture were measured by enzyme-linked immunosorbent assay(ELISA).The expression of the nuclear factor kappa-B(NF-κB)p65,nuclear factor of inhibitory kappa B alpha(IκBα),and Toll-like receptor-4(TLR4)were analyzed by Western blot.Results: CCK-8 assay demonstrated that DHA had no significant effect on cell viability exposure to the concentration was under 2μmol/L(p>0.05).The cell morphology change induced by LPS were mitigated by DHA.The gene expression of iNOS,IL-1β,IL-6,TNF-α in cells and the production of pro-inflammatory cytokines(IL-1β,IL-6,TNF-α)in LPS stimulation group were significantly attenuated by DHA(p<0.01).The increased expression of TLR4 and nuclear translocation of NF-κB p65 were suppressed by DHA as well as the decreased expression of IκBα in cytoplasm was attenuated by DHA(p<0.01).Conclusion:The DHA inhibits the activation and inflammatory response of BV-2 microglial cells induced by LPS,the anti-inflammatory effect may be due to the inhibition of TLR4/NF-κB signaling pathway.