Fig. 1

Ros. A induces differentiation in rabbit articular chondrocytes. Rabbit primary cultured articular chondrocytes were treated with or without the indicated concentrations of rosmarinic acid (Ros. A) for 24 h (a and c) or with 75 μg/mL Ros. A for the specified time periods (b and d). a and b The expression of type II collagen and actin was analyzed by western blotting (upper panel). Actin was used as a loading control. The relative amounts of type II collagen were quantified by densitometry measurements (Image J) (lower panel). c and d The synthesis of sulfated-proteoglycan was detected via alcian blue staining. The results represent three independent experiments. Values shown are the means ± SD; *p < 0.05 vs. control cells