Fig. 6
Ros. A induces differentiation and inflammatory response by p38 and ERK-1/−2 pathways. Chondrocytes were exposed to 75 μg/mL rosmarinic acid (Ros. A) in the absence or presence of 20 μM PD98059 (PD) or 20 μM SB203580 (SB) for 24 h. a Type II collagen, COX-2, MMP-13, pERK, pP38, and actin were detected by western blotting. Actin was used as a loading control (left panel). The relative amounts of proteins (Type II collagen, COX-2, MMP-13. pERK, pp38) were quantified by densitometry measurements (Image J) (right panel). b Production of sulfate proteoglycan was determined by alcian blue staining (upper panel). Synthesis of prostaglandin E2 (PGE2) was analyzed by PGE2 assays (lower panel). c Expression of type II collagen and COX-2 was detected by immunocytochemistry. The results represent three independent experiments. Values shown are the means ± SD; *p < 0.05 compared to the control; # < 0.05 compared to the Ros. A