Figure 6.

Glycyrrhizin suppressed interleukin-1β (IL-1β)-induced matrix metalloproteinase (MMP) expression in chondrocytes. Chondrocytes were co-treated with glycyrrhizin (5 mM) and IL-1β (10 ng/mL) for 24 hours. si-HMGB1 was transfected into chondrocytes 6 hours before the stimulation. MMP-1, MMP-3, and MMP-13 levels were determined by ELISA (A-C) (all n = 6). MMP-1, MMP-3, and MMP-13 mRNA expressions were assessed by qRT-PCR (D-F) (n = 3). All the experiments were also repeated independently 3 times. **P < 0.01, ***P < 0.001 compared with normal controls (NC), ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 compared with single IL-1β treatment.