假体与组织工程骨界面骨整合的生物学特征

Biological characteristics of osseointegration between implant and tissue-engineered bone

目的:假体骨组织界面的骨整合不佳是发生人工关节松动的主要原因之一。实验构建了羟基磷灰石/骨髓基质细胞组织工程骨以修复假体周围骨缺损,并观察假体-组织工骨界面愈合的生物学特性。方法:实验于2007-02/06在解放军济南军区总医院动物实验中心完成。①组织工程骨的构建:取大白兔1只抽取骨髓约5mL行细胞培养,传至第4代时将基础培养液更换为诱导液进行成骨诱导。将细胞密度调整到109L-1滴加于羟基磷灰石颗粒表面,在基础培养液内培养24h后更换诱导液培养1周。②实验方法:取健康清洁级新西兰大白兔15只,双侧股骨髁制作0.5cm×1.0cm的骨缺损,骨缺损处植入钛合金种植体,然后左侧种植体周围植入复合的组织工程骨为实验侧,右侧仅植入羟基磷灰石填充骨缺损为对照侧。③实验评估:术后4,8和12周分别行X射线检查,观察植入体周围成骨情况;麻醉后处死动物,行X射线能谱分析及种植体表面扫描电镜检查观察界面的生物学特性。实验过程中对动物的处置符合动物伦理学标准。结果:2只兔2侧发生骨折,余13只大白兔进入结果分析。①X射线检查示,术后12周实验侧植入体周围骨组织密度一致,植入体与骨组织之间无间隙,有骨小梁形成;对照侧植入体周围骨组织密度不均,植入体与骨组织之间有小范围低密度影。②X射线能谱分析示,随着时间的变化实验侧和对照侧内钙、磷元素质量分数都呈增大趋势,实验侧内钙磷元素质量分数先增大后减小,而对照侧内钙磷元素质量分数呈持续增大趋势。③扫描电镜示,12周实验侧组织工程骨与种植体已形成骨性连接,对照侧仍为纤维连接。结论:骨髓间充质干细胞诱导后复合珊瑚羟基磷灰石构建组织工程骨与种植体之间骨代谢活跃,骨整合速度快。

AIM： Poor osseointegration is one of the causes of artificial joint cinch. In this study, we constructed a hydroxyapatite ceramic/marrow stremal cells tissue-engineered bone for bone defect. The biological characteristics of the implant-tissue engineered bone interface were observed. METHODS： The experiment was conducted in Animal Experimental Center of General Hospital of Jinan Military Area Command of Chinese PLA from February to June 2007.①5 mL bone marrow aspirated from the thighbone of a rabbit was cultured and the inducing fluid was replaced from the fundamental nutrient solution until the fourth generation. Cells were dropped on the surface of the hydrexyapatite ceramic with the density of 10^9 L^-1. The fundamental nutrient solution was substituted by inducing fluid after 24 hours, and then the cells were cultured for 1 week. ②Cancellous bone defects （0.5 cm×1.0 cm） were created on bilateral femur condylar in 15 healthy clean New Zealand rabbits. After titanium alloy implant was implanted into the defects, compound tissue-engineered bone was implanted in the left implant as experimental group, and hydroxyapatite.ceramic （HAC）-filled bone was implanted in the right side as control group. ③X-ray analysis was performed at weeks 4, 8 and 12 postoperatively to observe bone formation around implants. Animals were sacrificed after anaesthesia. The biological characteristics were studied by X-ray spectrum analysis, scanning electron microscope （SEM） respectively at weeks 4, 8 and 12. Animal experiment was accorded with the animal ethical standard. RESULTS： Two New Zealand rabbits developed bilateral fracture and the other 13 rabbits were involved in the result analysis. ①X-ray examination showed that the density of bone tissue around the implant was aequalis, and the interspace between implant and bone tissue was filled with lots of bone trabeculars in experimental group at week 12 postoperatively. The density of bone tissue around the implant was inhomogeneous and low-density umbra existed in the interspace between implant and bone tissue in control group. ②X-ray spectrum analysis showed that the contents of the Ca and P in two groups augmented gradually with the time going by. The contents of Ca and P increased, and then reduced in the experimental group. The contents of Ca and P had the trend to increasing in control group. ③SEM showed that bony union appeared between tissue-engineered bone and implants at the experimental group at week 12, whereas fibrous joint appeared in the control group. CONCLUSION： Bone metabolism is active and the osseointegration is quick between implant and tissue-engineered bone composed of osteoblasts, which were induced from mesenchymal stem cells and hydrexyapatite.