Preliminary Study On The Regulation Of Quercetin On Macrophage Polarization Induced By Porphyromonas Gingivalis LPS

Objective: Peri-implantitis is a chronic oral inflammatory disease similar to periodontitis,which is associated with the polarization of macrophages in the course of disease development.Macrophage is an important defensive cell of organism,under the action of different stimulation factor,macrophage can present two kinds of differentiation state with different phenotype and physiological function.M1 macrophages can release IL-1,TNF-α,i NOS and other pro-inflammatory cytokines to promote the inflammatory response.These cytokines confer strong cytotoxicity and tissue damage to M1 macrophages,while killing pathogenic bacteria and causing the degradation of connective tissue and the absorption of bone tissue.M2 macrophages can release IL-10,Arg-1 and other anti-inflammatory factors to promote the repair and reconstruction of damaged tissue.Quercetin is an alcoholic compound of flavonoids,which has anti-inflammatory effects.The purpose of this experiment is to explore whether quercetin can inhibit the M1 polarization of macrophages,reduce the production and release of pro-inflammatory cytokines,and provide a theoretical basis for the inhibition of the development of peri-implantitis.Method: 1.RT-PCR method was used to detect the relative expression levels of i NOS and Arg-1 in P.g LPS stimulated macrophage cell line RAW264.7 in 24 h.2.Before the stimulation by P.g LPS,using Quercetin to pretreat the RAW264.7 cells for two hours.RT-PCR method was used to detect the m RNA expression of i NOS and Arg-1,and Elisa method to detect the expression of TNF-α and IL-10.3.The results statistics of the experiment were used by Graph Pad Prism software,single factor analysis of variance analysis.Results: 1.After the stimulation by P.g LPS,the m RNA expression of i NOS by RAW264.7 cells were significantly increased in 24 h,but the m RNA expression of Arg-1 had a slight increased.2.Using Quercetin to pretreat RAW264.7 cells for two hours showed the expression levels of i NOS and TNF-α were decreased dramatically,however,at the same time,the expression levels of Arg-1 and IL-10 had no significant change.Conclusion: Quercetin reduces the expression of inflammatory cytokines via inhibiting P.g LPS-activated RAW264.7 to the M1 polarization.