Divergent effects of suramin on in vitro and in vivo assays of cartilage degradation.

Proteinases are thought to be responsible for cartilage and bone erosion noted in chronic inflammatory conditions. Suramin [8-(3-benzamindo-4-meta-1-benzamindo)naphthalene-1,3,5-trisulfonic acid], 10(-5) and 10(-4) M, inhibited the release of a mouse macrophage-derived cartilage proteoglycan-degrading enzyme. At 10(-5) M it antagonized the activity of beta-glucuronidase and cathepsin D derived from the mouse macrophage, as well as similar enzymes secreted by rat macrophages in vivo. When cultured at 10(-4) M with rabbit knee cartilage, it antagonized the autolytic release of proteoglycan, indicating an inhibitory activity against a chondrocyte-derived neutral proteinase. After in vivo treatment at 10 mg/kg/day s.c., it was ineffective in preventing the cartilage and bone erosion noted in the adjuvant arthritic rat.