The effects of collagen fragments on the extracellular matrix metabolism of bovine and human chondrocytes

Cartilage matrix degradation generates collagen type II fragments. The obje ctive of this study is to explore the possibility that these collagen fragm ents may be part of an endogenous metabolic feedback. Initially, collagen f ragments were extracted from normal or osteoarthritic cartilage, as part of a matrix fragment preparation. Later, collagen fragments were generated by digestion of bovine collagen type II with bacterial collagenase (col2f). T hese fragments were added to cultures of isolated chondrocytes (bovine and human) and cartilage explants (human). In a dose-dependent manner, col2f ca used inhibition of cell attachment to collagen, inhibition of collagen synt hesis, and induction of matrix degradation. In addition, when col2f were ad ded to human cartilage explants, an induction of gelatinase activity was de tected in the media, These data sets present first evidence that degradatio n products of collagen may be directly involved in the regulation of cartil age homeostasis.