Figure 3: Western blotting for p38 kinase, JNK and STAT3. Human OA chondrocytes were grown to hyperdensity as previously described [18,25] and treated with rhTNF-α (10ng/ml) or not (C) for up to 60 min. Cytosolic protein lysate from the 1, 5, 30 and 60 min incubations were electrophoresed as previously described and Western blotting performed [25]. Panels A and B: Western blots were produced as previously described [25] using anti-phospho-p-38 MAPK antibody or an anti-p38 MAPK antibody; (Panel A), anti-phospho-SAPK p54 (JNK 2) antibody/anti-phospho-SAPK p46 (JNK 1) antibody or (Panel B) anti-SAPK p54 (JNK 2)/anti-SAPK p46 (JNK 1) antibody. Panel C: A Western blot was produced with the specific anti-U-STAT3 antibody or anti-phospho-STAT3 antibody as indicated in Materials and Methods. The bands migrating faster than the phospho-STAT3 standard have retained reactivity with anti-phospho-STAT3, but have not been fully characterized. These bands may represent degradation products of phospho-STAT3. The fastest migrating band reacting with anti-phospho- STAT3 was also present in the control (C) group.