CELL-FUNCTION DURING CHONDROGENESIS AND OSTEOGENESIS INDUCED BY BONE MORPHOGENETIC PROTEIN ENCLOSED IN-DIFFUSION CHAMBER - BIOCHEMICAL-STUDIES ON NATIVE PRODUCTS DERIVED FROM OUTSIDE DIFFERENTIATING CELLS

A diffusion chamber containing rabbit bone morphogenetic protein (BMP) was implanted in the abdominal muscle of a Sprague-Dawley rat. Outsid e of the chamber, cartilage differentiated one to two weeks after impl antation, and bone replaced the cartilage three to four weeks after im plantation. The interstitial fluid inside the chamber contained only b iologic substances produced by cells proliferating and differentiating outside of the chamber. To investigate the cell function during chond rogenesis and osteogenesis, alkaline phosphatase activity and the amou nts of S-100 alpha protein, S-100 beta protein, creatine kinase subuni ts M (CK-M), creatine kinase subunits B (CK-B), hyaluronic acid (HA), and chondroitin sulfate (CS) were measured in the supernatant of inter stitial fluid inside the chamber. Alkaline phosphatase activity increa sed two to four weeks after implantation. The amount of S-100 beta pro tein acutely increased during the fourth week. The amount of CK-B also increased during the fourth week. The increased levels of HA and CS w ere also observed after two to four weeks. The examination of such nat ive products may help not only to clarify the mechanisms of cartilage and bone development, but also to develop a sensitive bioassay for BMP .