Fig 1: SFRP4 Inhibits the Canonical Wnt Pathway to Accelerate NPCs Senescence. a-b. GSEA of mass spectrometry. c. Western blot analysis of SFRP4, Tumor protein P53 (P53), Cyclin-Dependent Kinase Inhibitor 1 A (P21), Cyclin-Dependent Kinase Inhibitor 2 A (P16) expression in nucleus pulposus tissues across G2 and G4. d. Western blot analysis of SFRP4, Glycogen Synthase Kinase 3 Beta (GSK3β), Phosphorylated Glycogen Synthase Kinase 3 Beta (P-GSK3β), β-catenin, P53, P21, P16 after different treatments of NPCs. e. β-Galactosidase staining was performed on NPCs subjected to various treatments. f. Western blot analysis of GSK3β, P-GSK3β, β-catenin, P53, P21, P16 after different treatments of NPCs. g. Double-immunofluorescence staining of COL1A1 and β-catenin. h. Double-immunofluorescence staining of ACAN and MMP2. i. Quantitative assessment of relative protein levels of SFRP4, P53, P21, P16, n = 3, P < 0.001. j. Quantitative assessment of relative protein levels of SFRP4, GSK3β, P-GSK3β, β-catenin, P53, P21, P16, n = 3, P < 0.001. K. β-Gal positive cells after different treatment. n = 3, P < 0.001. L. Quantitative assessment of relative protein levels of GSK3β, P-GSK3β, β-catenin, P53, P21, P16, n = 3, P < 0.001. M. Quantitative analysis of COL1A1 and β-catenin fluorescence intensity. n = 3, P < 0.001. N. Quantitative analysis of ACAN and MMP2 fluorescence intensity. n = 3, P < 0.001