Flautre B, Delecourt C, Blary M C, Van Landuyt P, Lemaître J, Hardouin P
I.R.M.S., Institut Calot, Berck-sur-Mer, France.
Bone. 1999 Aug;25(2 Suppl):35S-39S. doi: 10.1016/s8756-3282(99)00147-7.
Injectable calcium phosphate hydraulic cements (CPHC) are a new family of bone substitutes within the class of bone reconstruction biomaterials. In this work, CPHC were tested in two consistencies (preset blocks or liquid paste) in an experimental model of cancellous bone defect in sheep. The defects were eight times larger than those investigated previously in rabbits. Three delays (12, 24, and 52 weeks) were used. Before death, a double label of oxytetracycline and alizarine was made intravenously. The distribution of implants was randomized, histomorphometric evaluation was performed and compared with micrographic observation, and optical microscopy of stained sections was performed either under visible, ultraviolet, or polarized light. The results were compared with spontaneous healing of empty defects and with a control group of normal cancellous bone from sheeps of the same age. No significant difference has been observed between premolded and injected implants. In the sheep model, the degradation and new bone formation rates are three times slower, compared with those observed previously in rabbits. New bone formation increased from 5.9% (12 weeks) up to 11.0% (24 weeks) in the empty defect group. In the cement groups, 28.3% new bone was obtained at 12 weeks, which seemed then to level off (27.8% new bone at 24 weeks). Cement residues appear as radio-opaque cylinders on microradiographs. In all cases, a radiolucent layer was observed at the cement/bone interface at 24 weeks. Stained sections showed the formation of a fibroconnective capsule around the residual cement, which presumably slows down new bone formation. Nevertheless, quantitative bone remodeling was accelerated in the cement group; mineral apposition as well as adjusted apposition rates were higher, and the formation period as well as the mineralization of osteoid tissue were faster compared with empty cavities and controls. These results point to higher osteoblast activity and better exchange with surrounding tissues in the defects filled with cement.
可注射磷酸钙水硬性骨水泥（CPHC）是骨重建生物材料类别中的新型骨替代物。在本研究中，以两种稠度（预制块或液体糊剂）的CPHC在绵羊松质骨缺损实验模型中进行测试。缺损比先前在兔子中研究的缺损大八倍。采用了三个时间点（12周、24周和52周）。在处死前，静脉注射土霉素和茜素进行双重标记。植入物的分布是随机的，进行组织形态计量学评估并与显微图像观察进行比较，对染色切片在可见光、紫外线或偏振光下进行光学显微镜检查。将结果与空缺损的自然愈合情况以及来自同年龄绵羊的正常松质骨对照组进行比较。预成型和注射植入物之间未观察到显著差异。在绵羊模型中，与先前在兔子中观察到的情况相比，降解和新骨形成速率慢三倍。空缺损组新骨形成从5.9%（12周）增加到11.0%（24周）。在骨水泥组中，12周时获得了28.3%的新骨，随后似乎趋于稳定（24周时为27.8%的新骨）。骨水泥残留物在显微放射照片上呈现为不透射线的圆柱体。在所有情况下，24周时在骨水泥/骨界面观察到一个射线可透过层。染色切片显示在残留骨水泥周围形成了纤维结缔组织囊，这可能减缓了新骨形成。然而，骨水泥组的定量骨重塑加速；矿物质沉积以及调整后的沉积速率更高，与空洞和对照组相比，类骨质组织的形成期以及矿化更快。这些结果表明，在填充骨水泥的缺损中，成骨细胞活性更高，与周围组织的交换更好。
