中文摘要：

目的 观察可注射生物型骨水泥在修复兔股骨髁包容性骨缺损过程中的诱导成骨作用.方法 将rhBMP-2基因修饰的兔骨髓间质干细胞（BMSCs）用微囊包裹后与骨水泥复合,制成可注射生物型骨水泥,检测细胞存活及微观结构.制作标准试件检测其抗压强度,与单纯型骨水泥进行比较.取6只新西兰大白兔制作双侧股骨髁包容性骨缺损模型,随机一侧植入生物型骨水泥,对侧植入单纯型骨水泥.术后即日、6、12周摄X线片,术后12周处死行组织学观察,采用骨计量学方法测量骨水泥面积（CA）、矿化骨小梁面积（TBA）、成骨细胞指数（OBI）、破骨细胞指数（OCI）;免疫组化染色观察BMP-2、TGF-β1、VEGF因子的表达.结果 微囊化细胞与骨水泥复合后培养1周,细胞存活率达90%以上.生物型骨水泥内有羟基磷灰石结晶形成,材料呈现多孔样结构,孔径为2~6 μm.固化后1周抗压强度为（20.19±1.75） MPa,小于单纯型骨水泥的（30.21±4.60） MPa（P〈0.01）.X线片显示两种骨水泥均能完全填充骨缺损,生物型骨水泥降解速度略快.组织学观察可见骨水泥被吸收为数块,由新生骨小梁包绕,其间无纤维组织层介入.12周时生物型骨水泥CA为9.68%,小于单纯型骨水泥的17.47%（P〈0.01）;TBA为58.75%,大于单纯型骨水泥组的34.34%（P〈0.01）.OBT和OCT的两组差异无统计学意义.生物型骨水泥附近有大量椭圆形核肥大的细胞胞质为BMP-2染色阳性,中等量细胞有TGF-β1和VEGF阳性表达,数量均较对照组多.结论 将BMP-2引入磷酸钙骨水泥可以使其具有骨诱导活性：能诱导兔骨髓BMSCs趋化与增生,加快新骨形成;还可诱导细胞大量表达TGF-β1与VEGF,三种细胞因子之间的协同作用可加快磷酸钙骨水泥的降解成骨速度.

英文摘要：

Objective To evaluate the osteogenic functions of injectable biological bone cement during repairing inclusive bone defects in rabbit femoral condyles.Methods Encapsulated rhBMP-2 gene modified rabbit bone mesenchymal cells （BMSCs） were seeded into calcium phosphate cement （CPC） to prepare injectable biological bone cement.The live/dead cell ratio was detected by calcein-AM/ethidium homodime staining and cement microstructure examined by electron microscope.The anti-compression strength of CPC were tested.Inclusive bone defects were created in the bilateral femoral condyles of 6 rabbits.The biological CPC was implanted randomly at one side and pure CPC at the other side.The radiological films were taken immediately, at Weeks 6 ＆ 12 post-operation.The animals were sacrificed at Week 12 post-operation and both femoral condyles were retrieved to prepare decalcified slides.The morphometrologic parameters of bone tissue, such as cement area （CA）, calcified trabecular area （TBA）, osteoblast index （OBI） and osteoclast （OCI） were measured.Immunohistochemical staining was performed to detect the expressions of BMP （bone morphogenetic protein）-2, TGF （transforming growth factor）-β1 and VEGF （vascular endothelial growth factor）.Results The calcein-AM/ethidium homodimer staining showed that the live rate of encapsulated cells was over 90%.It was found under electron microscope that there was the formation of hydroxyapatite crystals and the presence of connective microporous structure.The anti-compression strength of biological cement was （20.19±1.75） MPa. And it was much less than that of pure CPC.Radiological study showed that both types of CPC could fill bone defects completely without gap.The biological CPC degraded a little faster.As demonstrated by decalcified slides, the cements were absorbed into numerous small blocks around newborn trabecule without insertion of fibrous tissues.CA decreased to 9.68% in biological CPC group and it was much less than 17.47% for pure CPC group