Modification by oral doxycycline administration of articular cartilage breakdown in osteoarthritis.

Oral administration of doxycycline has been shown to reduce the severity of articular cartilage breakdown in various animal models of osteoarthritis (OA). This disease modifying effect is associated with reductions in the levels of active and total collagenase and gelatinase in extracts of articular cartilage from the involved joint. These observations appear to justify a clinical trial of doxycycline, a readily available, inexpensive antimicrobial that has been used therapeutically in humans with OA for years with an excellent safety record.