Figure 4.

Anti-CD95 induced chondrocyte death is p38 MAPK dependent. (a) Western blot analysis of the levels of phosohorylated-p38 MAPK and p38 MAPK protein (left panel) and the quantification of the western blot by densitometric analysis (right panel). *P < 0.05 versus control. Each bar represents mean ± standard deviation of three experiments. (b) The levels of phosphorylated ATF-2 and ATF-2 protein were determined by western blot on the left. Quantification of the western blot by densitometric analysis is shown on the right. *P < 0.05 versus control. Each bar represents mean ± standard deviation of three experiments. (c) Caspase-3 activities were determined using a caspase-3 cellular activity assay kit. *P < 0.05 versus control. each bar represents mean ± standard deviation of three experiments. Anti-CD95: treatment with a mAb anti-Fas CH 11 (100 ng/ml) in serum-free medium for 17 hours. SB: treatment with SB203580 (10 μmol/l) for 17 hours. SB+Anti-CD95: treatment with SB203580 for 2 hours followed by anti-Fas treatment for 17 hours. Control: cells were treated with DMSO only. Results are representative of three OA cartilage samples. ATF, activating transcription factor; DMSO, dimethyl sulfoxide; mAb, monoclonal antibody; MAPK, mitogen-activated protein kinase; OA, osteoarthritis.