Decrease in interleukin (IL)-17-inducible matrix metalloproteinase (MMP)-3 and MMP-13 gene expression by mithramycin. Quiescent bovine chondrocytes (a) or primary human chondrocytes (b) were pretreated with different doses of mithramycin for 30 min and treated further with IL-17 for 24 hours. The MMP-3, MMP-13 and 28S RNA levels were measured by Northern hybridization, and MMP-13 protein levels were measured by Western blot analysis. For protein gels, 4 μg of protein was applied to each lane. The resulting autoradiograms indicating the respective gene products are shown.