Figure 1.

GDF-5 overexpression inhibits LPS-induced secretion of TNF-α and IL-1β from nucleus pulposus cells. In the LPS group (model of intervertebral disc degeneration), protein expression levels of (A) TNF-α and (B) IL-1β were significantly higher than those in the Ctrl group, and these levels were significantly repressed by GDF-5 overexpression. **P<0.01 vs. Ctrl group; ^#P<0.05 vs. LPS group. GDF-5, growth and differentiation factor-5; LPS, lipopolysaccharide; TNF-α, tumor necrosis factor-α; IL-1β, interleukin-1β; Ctrl, control.