Figure 3.

Effects of growth differentiation factor-6 (GDF-6) treatment on anabolic ACAN encoding aggrecan, COL2A1 encoding type II collagen, pro-inflammatory TNFA encoding tumor necrosis factor-α (TNF-α), interleukin (IL)-6, catabolic matrix metalloproteinases-3 (MMP-3), and a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4) gene expression in intervertebral disc nucleus pulposus cells. Cells of the moderate degeneration group (a) and severe degeneration group (b) were seeded on Tapered Stencil for Cluster Cultures and treated with solvent as a control (group C; set as 1.0), 100-μg/mL GDF-6 (group G), 10-ng/mL pro-inflammatory IL-1β (group I), or both (group G + I) for 48 h. Gene expression of ACAN, COL2A1, TNFA, IL-6, MMP-3, and ADAMTS-4 relative to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was assessed through real-time reverse transcription–polymerase chain reaction using SYBR Green. Data are the mean ± standard deviation as the fold change relative to the control (group C) (n = 6). One-way repeated-measures analysis of variance with the Tukey–Kramer post-hoc test was used. Significant differences were set as * p < 0.050 and ** p < 0.010.