Fig 2: Upregulation and downregulation of SDF1 expression in nucleus pulposus cells. (A) RT-qPCR showing that the mRNA expression level of SDF1 in the Up group was significantly upregulated compared with the D and NC groups. (B) RT-qPCR showing that the mRNA expression level of SDF1 in the Down group was significantly downregulated compared with the D and NC groups. (C) Western blot analysis showing the SDF1 expression level in the D, NC and Up groups. (D) The statistical results of (C), showing that SDF1 expression in the Up group was significantly increased compared with the D and NC groups. (E) Western blot analysis showing the SDF1 expression levels in the D, NC and Down groups. (F) The statistical results of (E), showing that SDF1 expression in the Down group was significantly decreased compared with the D and NC groups. **P<0.01, ***P<0.001 vs. respective D group. #P<0.05, ###P<0.001 vs. respective NC group. D, degeneration; NC, negative control; Up, upregulation; Down, downregulation; RT-qPCR, reverse transcription quantitative PCR; SDF1, stromal cell derived factor 1.

Fig 3: CXCL12 neutralizing antibody relieves SNI-induced hyperalgesia. A Experimental diagram of multiple intravenous injection (i.v.) of CXCL12 neutralizing antibody in SNI model mice. The black lines represent mechanical pain behavioral tests. The blue lines show injection of anti-CXCL12 antibody (ab9797, Abcam, 20 ng/200 μl, once a day for 8 days) and the red line indicates sham surgery or SNI time point. B Continuous i.v. injection of anti-CXCL12 antibody partially alleviated ipsilateral mechanical allodynia caused by SNI (half male in each group). *P < 0.05, **P < 0.01, ***P < 0.001 vs. intravenous vehicle and sham control group (Vehi + anti-CXCL12) # P< 0.05, ## P < 0.01, ### P < 0.001, #### P < 0.0001 vs. intravenous vehicle and SNI group (Vehi + SNI)

Fig 4: DUX4-transfected cells overexpress SDF1 and CXCR4Immunofluorescence analysis of CXCR4 and DUX4 expression in human immortalized myoblasts (MB) (A) and bone marrow-derived mesenchymal stromal cells (BMSCs) (B) 24 h after the transfection with pCI-NeoDUX4 plasmid. Formaldehyde-fixed cells were stained with CXCR4, SDF1 and DUX4 antibodies, representative images are shown; scale bar 50 μm.

Fig 5: SDF1 immunofluorescence of nucleus pulposus cells in the Down, D and Up groups. The fluorescence intensity in the Down group was the weakest, and the fluorescence intensity in the Up group was the strongest. Magnification, ×200. Down, downregulation; D, degeneration; Up, upregulation; SDF1, stromal cell derived factor 1.