Figure 4

Inhibition of IL-1β-stimulated phosphorylation of p38-MAPK by PE in primary human OA chondrocytes. (a) Primary human OA chondrocytes were pretreated with PE for 2 h and then stimulated with IL-1β for 30 minutes and total cell lysate proteins were resolved by SDS-PAGE and analyzed by Western immunoblotting using primary antibodies specific for phospho-p38-MAPK and total p38-MAPK. (b) Inhibition of IL-1β-stimulated phosphorylation of p38-MAPK isoforms by PE in primary human OA chondrocytes. Primary human OA chondrocytes were pretreated with PE for 2 h and then stimulated with IL-1β for 30 minutes and total cell lysate were used to immunoprecipitate p38-α, γ and δ -MAPKs using monoclonal antibodies specific for each isoform as described above. Immunoprecipited protein was resolved by SDS-PAGE and Western blots were probed with anti-phospho-p38-MAPKantibody. Band images were digitally captured and the band intensities (pixels/band) were obtained as described under Figure 1. Average pixel values presented as mean ± SD; data without a common letter differ, P < 0.05.