Research Article
Effects of OP-1 and PTH in a new experimental model for the study of metaphyseal bone healing
Article first published online: 16 MAY 2007
DOI: 10.1002/jor.20420
Copyright © 2007 Orthopaedic Research Society
Additional Information
How to Cite
Tsiridis, E., Morgan, E. F., Bancroft, J. M., Song, M., Kain, M., Gerstenfeld, L., Einhorn, T. A., Bouxsein, M. L. and Tornetta, P. (2007), Effects of OP-1 and PTH in a new experimental model for the study of metaphyseal bone healing. J. Orthop. Res., 25: 1193–1203. doi: 10.1002/jor.20420
Publication History
- Issue published online: 17 AUG 2007
- Article first published online: 16 MAY 2007
- Manuscript Accepted: 14 MAR 2007
- Manuscript Received: 6 APR 2006
- Abstract
- References
- Cited By
Keywords:
- metaphysis;
- fracture healing;
- osteotomy;
- bone morphogenetic protein-7;
- torsion
Abstract
The purpose of this study was to establish a reliable model of metaphyseal bone healing and to use this model to investigate the effect of recombinant human osteogenic protein 1 (rhOP-1; BMP-7) and parathyroid hormone fragment (PTH 1–34) on healing. A wedge-shaped osteotomy was created in the distal tibia of 16-week-old female New Zealand White rabbits (n = 20) and was bridged with a custom-made external fixator. Five experimental groups of four animals each were investigated. In groups 1–4 the osteotomy gap was filled with tricalcium phosphate (TCP), and the gap was left unfilled in group 5 (“normal healing”). In group 1, 200 µg OP-1 was mixed in with the TCP. Groups 2 and 3 received daily subcutaneous injections of 10 and 40 µg/kg PTH, respectively, beginning on postoperative day 1. Radiographs were taken weekly. Following sacrifice on postoperative day 28, peripheral quantitative computed tomography (pQCT), histology, and mechanical testing (axial compression and torsion) were performed. Only one animal failed to complete the full 4-week time course, and no infections were encountered. Bone healing occurred in all animals. OP-1 stimulated bone formation locally, while the lower dose of PTH enhanced bone formation systemically (p < 0.05). Tibiae treated with OP-1 exhibited higher torsional strength (p = 0.04) than those in the normal healing group. These results indicate that a reliable and reproducible surgical model of metaphyseal healing has been established. In addition, differences in systemic versus local effects of PTH and OP-1 in accelerating metaphyseal fracture healing were found. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1193–1203, 2007

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