Fig. 3. Effect of oleanolic acid on the gene expression of MMP-1, MMP-13, ADAMTS-4, ADAMTS-5, or collagen type II in rabbit chondrocytes.

Primary cultured rabbit articular chondrocytes were pretreated with varying concentrations (1, 10, 50, and 100 µM) of oleanolic acid for 2 h and then stimulated with IL-1β (10 ng/mL) for 24 h. The gene expression level of MMP-1, MMP-13, ADAMTS-4, ADAMTS-5, or collagen type II was measured by RT-PCR.