Bone matrix-induced local bone induction.

The sequential cellular changes in the implants in response to collagenous bone matrix-induced local bone formation include: binding of fibronectin to matrix, chemotaxis and attachment of progenitor cells, proliferation and differentiation of progenitor cells into chondrocytes, and finally osteogenesis and marrow differentiation. The cellular origin of osteogenic proteins is not clear. The present study compares the osteogenic potential of demineralized rat and porcine bone matrix by dissociative extraction and reconstitution. Judging from the Sephacryl S-200 gel filtration profiles of the dissociative extracts of rat and porcine matrix, the latter appears to be smaller. Under identical experimental conditions, the rat chondrosarcoma and osteosarcoma were examined for chondrogenic and osteogenic properties and found to be devoid of inductive potential. It is noteworthy that gel filtration fractions of rat chondrosarcoma on Sepharose CL-6B are inhibitory to bone inductive potential of demineralized rat bone matrix.