CCL2 and intervertebral disk degenerative disorder: The expression levels of CCL2, AKT1, STAT3 and VEGFA were significantly lower in the degenerated disc, whereas expression of CXCL8, IL2, FAM49B and PLG were significantly higher in degenerated human discs compared to healthy discs, suggesting that these genes might play a role in IDD pathogenesis (Figure 5A).