mRNA expression levels of catabolic mediators. mRNA expression levels for nucleus pulposus (NP) constructs (n = 3) after treatment with interleukin-1 beta (IL-1β) or interleukin-1 receptor antagonist (IL-1ra) conditioned media or both were quantified, normalized to glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and expressed as a ratio to untreated constructs. (a) Inducible nitric oxide synthase (INOS). (b) A disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4). (c) Matrix metalloproteinase 13 (MMP-13). (d) IL-1β. (e) IL-6. (f) Toll-like receptor 4 (TLR-4). Values are mean ± standard deviation. *P < 0.05 versus untreated constructs; ◆P < 0.05 versus IL-1β-only treated constructs.
Gorth et al. Arthritis Research & Therapy 2012 14:R179 doi:10.1186/ar3932