Figure 2

Activation profile of p38-MAPK in IL-1β-stimulated primary human OA chondrocytes. (a) Primary human OA chondrocytes (70 to 80% confluent) were incubated with IL-1β (10 ng/ml) for 5 to 120 minutes, and then the phosphorylation of p38-MAPK was determined by Western immunoblot analysis using primary antibodies specific for phospho-p38-MAPK and p38-MAPK. (b) SiRNA-mediated knockdown of MKK3 and p38-MAPK phosphorylation in IL-1β-stimulated human OA chondrocytes. MKK3-siRNA (30 to 300 nM) transfected human OA chondrocytes were incubated with IL-1β (10 ng/ml) for 30 minutes, then the phosphorylation of p38-MAPK was determined by Western immunoblot analysis. (c) SiRNA-mediated knockdown of MKK6- and p38-MAPK phosphorylation in IL-1β-stimulated human OA chondrocytes. MKK6-siRNA (30 to 300 nM) transfected human OA chondrocytes were incubated with IL-1β (10 ng/ml) for 30 minutes, then the phosphorylation of p38-MAPK was determined by Western immunoblotting. Band images were digitally captured and the band intensities were obtained using UN-San-It software and are expressed in average pixels/band. Data shown are cumulative of two experiments. Average pixel values presented as Mean ± SD; data without a common letter differ, P < 0.05.