非陶瓷型人工骨体内降解过程的超微结构观察

目的]评价自行合成的CPC和CPC／BMP复合人工骨的成骨能力、降解性能以及植入体内后的骨结合能力。方法]参考文献方法合成CPC，并将其作为BMP的载体制成CPC／BMP复合物，植入小鼠肌袋和兔桡骨15mm骨缺损，通过扫描电镜观察新骨形成和材料的变化，综合评价材料在骨缺损修复中的作用。结果]CPC植入小鼠肌袋内不能诱导成骨，CPC／BMP植入后有新骨形成，同时材料出现降解。植入骨缺损后，CPC／BMP复合物和单纯的CPC均可以促进新骨形成，但后者骨修复能力弱，材料降解速度缓慢。植入4周有新骨形成，材料形态出现变化，晶体结构被逐渐破坏。24周有板层骨长入并与材料紧密结合，骨缺损初步修复，材料被溶解成规则的蜂窝状框架结构。X-射线能谱分析结果表明，随着时间的延长，新骨钙化程度逐渐增高，24周时已经与正常骨接近。结论]CPC／BMP生物活性人工骨降解性能理想，对骨缺损有较强的修复能力，可望成为新型的骨缺损修复材料。

UItrastructural observation on the degradation of calcium Phosphate Cement implanted into muscle or bone and the osteogenetic character

Objective] To evaluate the degradation rate, osteogenetic character and bone-bonding capability of calcium phosphate cement (CPC) before and after combined with bone morphogenetic protein (BMP). Methods] A new type of non-ceramic hydroxyapatite cement of CPC was synthesized, and CPC/BMP composite was prepared to study its biode-grade rate, osteogenetic character and bone-bonding capability through inner-muscle implant test and inner-bone implant test. Samples were observed by scanning electron microscope (SEM) and energy dispersion analysis X-ray (EDAX). Results] When the composite was implanted into muscle pouches of mice, new bone formation was observed with significant degradation of the material. No new bone formation and degradation was found in CPC group. When CPC/BMP was implanted into 15mm-defect in the middle of the radial diaphysis of rabbit, new bone bridged the gap between the proximal and distal fragments by the end of 24 weeks, most of the composite was degraded and absorbed. Only little new bone formed in CPC group and no visible degradation was found. Calcification was significantly higher in CPC/BMP group than that in CPC group as implied by EDAX. Conclusion] BMP is helpful in the degradation of CPC, and CPC/BMP composite has ideal degradation rate with great potential in bone defects repairing, so it can be used as grafting material in dealing with segmental bone defect in clinic.