Application of octacalcium phosphate for bone substitutes and a carrier for bone morphogenetic protein

人工合成磷酸八钙（OCP）植入小鼠骨膜下区可促进骨形成。植入的QCP可能被多核巨细胞吸收，这些细胞与破骨细胞具有某些超微结构特征，并随着时间的推移被骨所取代。我们假设OCP可以作为一种有效的骨替代物。为了验证这一假设，本研究旨在研究OCP植入是否能增强大鼠颅骨缺损的骨修复。大鼠分为两组：ocp治疗组和未治疗组。植入后4周、12周、24周，各组各取6只固定。在顶骨处制作全层标准环甲缺损，并将合成OCP植入缺损内。经影像学检查后，标本脱钙并进行组织学处理。与对照组相比，OCP植入显著促进骨修复。统计分析显示，在第4周至第12周期间，颅骨缺损内的放射不透明面积增加。组织学上，在第4周，骨在植入的OCP上和沿缺缘形成。在第12周，植入的OCP被新形成的骨包围。在第24周，缺损几乎完全被骨填满。在对照组中，仅沿缺损边缘观察到骨形成。结果表明，OCP可作为一种有效的骨替代物。

Synthetic octacalcium phosphate (OCP) enhances bone lbrmation if implanted into the subperiosteal region of murine bone. Such implanted QCP may be resorbed by the multinucleated giant cells which share some ultrastmctural characteristics with osteoclasts and replaced by bone with time. We hypothesized that OCP could be used as an effective bone substitute. To test this hypothesis, the present study was designed to investigate if bone repair in a rat skull defect is enhanced by the implantation of OCP.Rats were divided into two groups : OCP-treated animals and untreated controls. Six rats from each group were fixed at4, 12, and 24 weeks after implantation. A full-thickness standardized trephine defect was made in the parietal bone and synthetic OCP was implanted into the defect. After being examined radiographically, the specimens were decalcifled and processed for histology.OCP implantation significantly promoted bone repair compared to the controls. A statistical analysis showed an increase in the area of radiopacity within the skull defect between week 4 and week 12. Histologically, bone was formed on the implanted OCP and along the defeut margin atweek4. At week 12, the implanted OCP was surrounded by newly formed bone. At week 24, the defect was almost completely filled with bone. In the control, bone formation was observed only along the defect margin.The present results demonstrate that OCP could be used as an effective bone substitute.