Glycosaminoglycan (GAG) release and GAG, DNA, and GAG/DNA content in cultured nucleus pulposus cells (NPCs) treated with 10 or 100 ng/ml rhBMP-7. A. NPC pellets treated with rhBMP-7 show a significant dose-dependent increase in cumulative GAG release into the medium compared with the negative control. B. Regardless of the culture condition, DNA content of the NPC pellets was significantly lower compared with DNA content at day 0 (DNA0; dashed line), indicated by #. NPC pellets treated with 100 ng/ml rhBMP-7 showed a significantly higher DNA content at day 28 compared with the negative control and the 10 ng/ml rhBMP-7-treated NPC pellets. C, D. A significant increase in GAG content and GAG/DNA at day 28 was shown in the 100 ng/ml rhBMP-7-treated NPC pellets compared with the negative control and the 10 ng/ml rhBMP-7-treated NPC pellets. Data are expressed as mean ± SD. **Indicates significant difference at a 99% confidence interval (CI); *indicates significant difference at a 98% CI; # indicates a significant difference at a 99% CI.