The synovial production of collagenase and chondrocyte activating factors in response to cobalt

Abstract

Addition of CoCl₂ solutions to the culture media of confluent monolayers of lapine or human synoviocytes stimulated their production of the neutral proteinases collagenase, gelatinase, and caseinase. With lapine cells, maximum stimulation occurred at 10⁻⁷ M CoCl₂, while human cells required 10⁻⁴–10⁻⁵ M CoCl₂ to achieve a maximum stimulation. Production of prostaglandin E₂ by lapine cells was enhanced some 30–40% by concentrations of CoCl₂ that maximally stimulated synthesis of the neutral proteinases, whereas all concentrations of CoCl₂ slightly depressed the productio of prostaglandin E₂ by human celis. Lapine synovial cells that had been stimulated by CoCl₂ also produced a substance, or substances, that provoked the synthesis of collagenase, gelatinase, caseinase, and prostaglandin E₂ by monolayers of articular chondrocytes. Chondrocytes themselves, however, resisted activation by CoCl₂. These findings may be relevant to the aseptic loosening of joint prostheses.