Fibroblast growth factor enhances the interleukin-1-mediated chondrocytic protease release.

The unfractionated macrophage-conditioned medium stimulates the chondrocytes to produce high levels of proteases. Purified IL-1 preparations exhibit significantly lower activity towards chondrocytes. This IL-1 mediated effect can be enhanced in presence of fibroblast growth factor, suggesting that other factors may collaborate with IL-1, in events leading to the cartilage destruction in vivo.