Effects of Total Saponins from Dioscorea Nipponica Makino on Monosodium Urate-Induced M1-Polarized Macrophages through Arachidonic Acid Signaling Pathway: An in vitro Study

Objective:To investigate and reveal the underlying mechanism of the effect of total saponins from Dioscoreae nipponica Makino(TSDN) on the arachidonic acid pathway in monosodium urate(MSU)crystal-induced M1-polarized macrophages.Methods:M1 polarization of RAW264.7 cells were induced by1μg/mL lipopolysaccharide(LPS).The methylthiazolyldiphenyl-tetrazolium bromide method was then used to screen the concentration of TSDN.MSU(500 μg/mL) was used to induce the gouty arthritis model.Afterwards,10 μg/L TSDN and 8 μmol/L celecoxib,which was used as a positive control,were added to the above LPS and MSU-induced cells for 24 h.The mRNA and protein expressions of cyclooxygenase(COX) 2,5-lipoxygenase(5-LOX),microsomal prostaglandin E synthase derived eicosanoids(mPGES)-1,leukotriene B(LTB)4,cytochrome P450(CYP) 4A,and prostaglandin E2(PGE2) were tested by real-time polymerase chain reaction and Western blotting,respectively.The enzyme-linked immunosorbent assay was used to test the contents of M1 markers,including inducible nitric oxid synthase(NOS) 2,CD80, and CD86.Results:TSDN inhibited the proliferation of M1 macrophages and decreased both the mRNA and protein expressions of COX2,5-LOX,CYP4A,LTB4,and PGE2(P<0.01) while increased the mRNA and protein expression of mPGES-1(P<0.05 or P<0.01).TSDN could also significantly decrease the contents of NOS2,CD80,and CD86(P<0.01).Conclusion:TSDN has an anti-inflammation effect on gouty arthritis in an in vitro model by regulating arachidonic acid signaling pathway.