Comparative study of bone marrow induced by purified BMP and recombinant human BMP-2

Into a calf muscle pouch in Wistar rats, 50 micrograms purified bone morphogenetic protein (pBMP) or 50 micrograms recombinant human bone morphogenetic protein-2 (rhBMP-2) was implanted using atelopeptide type I collagen solution (CL) as a carrier. Three weeks later bone and bone marrow were induced in both groups. These induced bone and bone marrow were studied histologically. In the pBMP+CL group (n = 5), rich bone matrix and little bone marrow were observed. There was no fatty marrow or angioid tissue observed. In the rhBMP-2+CL group (n = 5), bone matrix and rich marrow including fatty marrow and angioid tissue were observed around and among the bony trabeculae. It was suggested that a "self-supporting bone organ" was induced.