Fig. (3) Impact of TGF-β1, OSM, TNF-α, IL-1β and IL-17 on TIMP-4 RNA expression in normal human knee primary chondrocytes kept in serum-deficient medium for 24 h, subjected to the indicated treatments and RNA levels analyzed by TIMP-4 and GAPDH RT-PCR. The results are cumulative representative of three independent experiments. On the bottom panel, quantitative analysis of TIMP-4 versus GAPDH RNA is shown: p < 0.01 Control versus TGF-β and IL-17; ** p < 0.05 Control versus OSM*. Whiskers in the graph represent means ± SEM. TIMP-4 protein levels (except IL-17, not determined) measured by Western blot analysis are also shown.