Abstract
Partially purified bone morphogenetic protein (BMP) was mixed with either insoluble bone matrix (IBM) or collagen (COL) derived from IBM. The bone collagen fibers were treated by digesting with pepsin to remove the antigenesity. BMP composites were implanted into the dorsal subcutaneous tissue of 4-week-old male rats. Each composite was removed at 1 and 2 weeks after implantation, and the ectopic-induced hard tissues were observed by routine histology. In BMP-ISM, bone was induced in a process resembling an endo-chondral ossification mode with antigenesity. In BMP-COL, much chondro-osseous tissue and fibrous bone formation were observed at 2 weeks, and the amount of induced hard tissues was much more than that in BMP-IBM. The collagens did not cause remarkable immunogenic response. These results suggested that bone collagen is superior as a carrier of BMP.
