Formononetin inhibits lipopolysaccharide-induced inflammation in nucleus pulposus mesenchymal stem cells

Yu Qinghe; Cai Ziming; Tian He; Li Pian; Ruan Ye; Liang Jinzhu; Lin Shuhui; Lin Wenping

doi:10.12307/2025.527

Abstract：BACKGROUND:Formononetin demonstrates potent anti-inflammatory and antioxidant abilities.However,its protective effect on nucleus pulposus mesenchymal stem cells is not yet clear. OBJECTIVE:To investigate the effect and mechanism of formononetin on nucleus pulposus mesenchymal stem cells under an inflammatory microenvironment. METHODS:(1)Primary nucleus pulposus mesenchymal stem cells were isolated from the intervertebral discs of SD rats,and flow cytometry was performed to identify the surface markers of mesenchymal stem cells.(2)The CCK-8 assay was employed to evaluate the impact of lipopolysaccharide and formononetin on the proliferation viability of nucleus pulposus mesenchymal stem cells,aiming to determine the appropriate concentration of formononetin for subsequent cell treatments.(3)An inflammatory microenvironment was simulated by adding 5 μg/mL lipopolysaccharide to the DMEM/F-12 culture medium,and nucleus pulposus mesenchymal stem cells were treated with different concentrations of formononetin for 24 hours.Levels of inflammation markers were detected using western blot assay,real-time quantitative PCR,and immunofluorescence.Western blot assay was conducted to measure the protein levels of the nuclear factor kappa B signaling pathway. RESULTS AND CONCLUSION:(1)The nucleus pulposus mesenchymal stem cells cultured in adherent wall were shuttle-shaped with good growth status.The results of flow cytometry showed that the surface markers of mesenchymal stem cells were positive for CD29,CD44,and CD90,and the surface markers of hematopoietic stem cells were negative for CD34 and CD45.(2)The treatment with formononetin at 12.5,25,50,100,and 200 μmol/L concentrations for 24 hours had no significant proliferation inhibitory effect on nucleus pulposus mesenchymal stem cells.Compared with the lipopolysaccharide group,the cell viability of nucleus pulposus mesenchymal stem cells treated with 12.5,25,and 50 μmol/L formononetin for 24 hours was significantly increased,so formononetin at 12.5,25,and 50 μmol/L concentrations was subsequently selected as the low,medium,and high concentrations for treating nucleus pulposus mesenchymal stem cells.(3)Compared with the lipopolysaccharide group,the protein and mRNA expressions of matrix metalloproteinase-3,matrix metalloproteinase-13,and tumor necrosis factor-α in nucleus pulposus mesenchymal stem cells in the low,medium,and high concentrations of formononetin groups were significantly decreased(P＜0.05)in a dose-dependent manner.(4)Compared with the lipopolysaccharide group,the expressions of phosphorylated nuclear factor kappa B and phosphorylated nuclear factor kappa B inhibitor protein in nucleus pulposus mesenchymal stem cells in the low,medium,and high concentrations of formononetin groups were significantly decreased(P＜0.05)in a dose-dependent manner.The above results suggest that formononetin may attenuate lipopolysaccharide-induced inflammation in rat nucleus pulposus mesenchymal stem cells by inhibiting the activation of the nuclear factor kappa B signaling pathway.