RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN-2 IS SUPERIOR TO DEMINERALIZED BONE-MATRIX IN REPAIRING CRANIOTOMY DEFECTS IN RATS

The purpose of this study was to measure bone-regenerative effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) in rat calvarial critical-size defects (CSDs). CSDs (8 mm in diameter) were treated with either: 1) 2.2 mu g rhBMP-2 combined with insoluble collagenous bone matrix (ICBM), 2) 6.5 mu g 8 rhBMP-2 plus ICBM, 3) ICBM alone, or 4) demineralized bone matrix (DBM), for 7, 14, or 21 days. Multiple linear regression showed that rhBMP-2 had a significant time- and dose-dependent effect on bone regeneration (P < .05). After 7 days, new calcifying cartilage and remineralizing ICBM, with an occasional zone of new woven bone, was evident in defects treated with rhBMP-2/ICBM. By 14 days, both doses of rhBMP-2 reconstituted with ICBM had induced more bone formation than ICBM alone or DBM, and 6.5 mu g was superior to 2.2 mu g, There was no evidence of adverse cellular response. This study shows for the first time that rhBMP-2 could restore osseous form to a calvarial defect. In addition, osteoregeneration was accelerated by the higher dose of rhBMP-2. (C) 1994 John Wiley & Sons, Inc.