Figure 4.

Effects of paeoniflorin on the expression of MMPs and TIMP-1. (A) Western blotting and (B) quantified western blotting results for MMP-1, MMP-3, MMP-13 and TIMP-1. Chondrocytes were pretreated with 0, 25 or 50 µM paeoniflorin for 3 h, followed by stimulation with IL-1β (10 ng/ml) for 24 h. Protein expression was assessed using western blotting with β-actin as a control. *P<0.05 vs. IL-1β alone and ^#P<0.05 vs. negative control. MMP, matrix metalloproteinase; TIMP, tissue inhibitor of MMP; IL, interleukin.