Expression of bovine MMP-1 and MMP-3 mRNA. Cartilage from (a, b) monoculture (n = 5, with two replicates each) and (c, d) human mRNA/protein in synovial fibroblasts (SFB) after co-culture with cartilage (n = 5, with two replicates each) with/without stimulation with TNF-α, IL-1β or TNF-α/IL-1β (14 days) were used.gene expression values (means ± standard error of the mean (SEM)), as determined by quantitiative PCR, are expressed as percentage of the values in non-stimulated samples (100%). In addition, (e, f) the values for human MMP-1 and MMP-3 protein secreted by SFB into the supernatant of co-cultures are shown. The protein levels, as measured in the supernatant by ELISA, are expressed as means +/- SEM. § p ≤ 0.05 Mann-Whitney U Test compared with non-stimulated control; * p ≤ 0.05 Mann-Whitney U Test compared with stimulation with TNF-α.