组织工程骨-假体界面微观结构与元素分析的意义

目的研究假体-组织工程骨界面的微观结构和钙磷元素及构成比动态变化及意义。方法取新西兰大白兔15只,将兔骨髓间充质干细胞培养、扩增及诱导后,与珊瑚羟基磷灰石复合构建组织工程骨;双侧股骨髁分别制作一0.5cm×1.2cm骨缺损,骨缺损中央植入0.2cmx1.0cm钛合金植入体,左侧植入体周围植入组织工程骨,右侧仅植入珊瑚羟基磷灰石为对照,于术后4周、8周和l2周分别行X线检查、扫描电镜及能谱分析观察植入体表面微观结构和钙磷元素百分含量及比值的变化。结果 X线检查示,实验组术后8-12周可见大量模糊的高密度骨痂影,缺损区与周围骨质间分界变模糊。对照组各时间点无明显变化;扫描电镜示,实验组术后8、12周植入体表面孔隙内有大量无定形物质,而对照组未见有无定形物质。能谱分析示,不同时间点实验组较对照组内钙、磷元素百分含量高,有显著性差异（〈0.05）,随着时间的变化实验组和对照组Ca、P百分含量都呈增高的趋势,但12周和8周相比无显著性差异（〉0.05）。实验组内钙磷比值随时间变化有逐渐增大趋势,8周时达峰值,8周后缓慢下降。结论假体-组织工程骨界面钙、磷元素及构成比的动态变化表明骨整合的形成,并随着时间的延长骨改建逐步增加。

Significance of Morphologic and Element Analyses on the Interface of Implant-Tissue Engineering Bone

Objective To evaluate the microstructure and dynamic change of chemistry elements on the implant-tissue engineering bone interface. Methods Fifteen New Zealand rabbits were studied. Bone mesenchymal stem cells cultured, differentiated, and induced were combined with hydroxyapatite ceramic to construct tissue engineering bone. Cancellous bone defects （0.5×1.2cm） were developed on bilateral condyles of femur. Tissue engineering bone were implanted surrounding the titanium alloy implant of the left,and the right were implanted with hydroxyapatite ceramic only. The microstructure and dynamic change of chemistry elements on the implant-tissue engineering bone interface were studied postoperatively by X-ray examination, scanning electron microscope, spectrum analysis respectively at 4,8,12 weeks. Results A great quantity of fuzzy and high-density osteotylus shadow was showed by X-ray in experimental group after eight weeks. The demarcation of the defect area and the bone tissue formed around the implant was blurred. There is no obviously changed at different time in control group. Scanning electron microscope notified that amount of amorphous material on pores of the implant surface increased gradually with time going by in experimental group. X-Ray spectrum analysis showed the percent content of the calcium and phosphate in the experimental group was statistically higher than the numbers of the control group at different tim（p〈 0.05）. With the time going by, the percent content of the calcium and phosphate in two sets both have a tendency to rise gradually. But there is no statistically significance at 12 weeks postoperatively contrast with the numbers of 8 weeks. The ratio between calcium and phosphate got larger with the time going by,and reached a peak at 8 weeks. Conclusion The microstructure and dynamic change of chemistry elements on the implant-tissue engineering bone interface show the formation of osteointegration. Osteointegration gets more and more with the time going by.