血管内皮生长因子复合纳米羟基磷灰石人工骨修复兔桡骨缺损

Repairing bone defects with vascular endothelial growth factor/nano-hydroxyapatite composite artificial bone

背景:血管内皮生长因子能促进血管内皮生长和血管生成,但其半衰期短,代谢降解快,不能在局部形成有效浓度。目的:观察血管内皮生长因子复合纳米羟基磷灰石人工骨修复兔桡骨缺损的效果。设计、时间及地点:随机分组设计、动物对照观察,于2006-12/2007-11在深圳市药检所实验室及深圳市第二人民医院中心实验室完成。材料:清洁级雄性新西兰大白兔60只。纳米羟基磷灰石人工骨,孔隙直径100～250μm,孔隙率为90%,将血管内皮生长因子165与纤维蛋白原混合液均匀黏附于纳米羟基磷灰石人工骨各孔道支架表面,再利用凝血酶原吸附在最外层,形成一层膜状结构,包埋血管内皮生长因子,使其维持蛋白活性并达到缓释目的。方法:建立兔单侧桡骨1cm缺损动物模型60只,按随机数字表法分为3组,血管内皮生长因子/纳米羟基磷灰石组、纳米羟基磷灰石组、羟基磷灰石对照组,每组20只。骨缺损处分别植入血管内皮生长因子与纳米羟基磷灰石人工骨、单纯纳米羟基磷灰石人工骨、普通羟基磷灰石人工骨。主要观察指标:植入后2,4,8,12周分别行X射线、组织学、免疫组织化学检查,观察人工骨早期血管化及成骨情况。结果:60只兔均进入结果分析。各时间点血管内皮生长因子复合纳米羟基磷灰石组X射线和组织学评价骨形成情况均高于纳米羟基磷灰石组、羟基磷灰石对照组,差异有显著性意义(P<0.05)。免疫组织化学染色结果表明,复合血管内皮生长因子的纳米羟基磷灰石人工骨、单纯纳米羟基磷灰石人工骨均可见新骨形成,前者早期血管化更明显,新骨形成更快,量更大,骨缺损修复能力明显优于后者。结论:血管内皮生长因子可促进纳米羟基磷灰石人工骨早期血管化,能加快骨缺损的修复。

BACKGROUND： Vascular endothelial growth factor （VEGF） could improve the growth of vascular endothelial cells and the formation of blood vessels, but its half-life is so short, metabolism is so fast, that it could not form the effective concentration in local site. OBJECTIVE： To observe the capability of VEGF/nano-hydroxyapatite （n-HA） artificial bone graft in the repairs of rabbit radius defect. DESIGN, TIME AND SETTING： The experiment, a randomized control animal study, was performed in the laboratory of Shenzhen Institute for Drug Control and the central laboratory of Shenzhen Second People＇s Hospital from December 2006 to November 2007. MATERIALS： A total of 60 New Zealand male white rabbits of clean grade were recruited. The n-HA artificial bone was used, at a porosity 90% and pore diameter 100-250 μm. VEGF165 combining with fibrinogen were stick on the surface of n-HA artificial bone. By means of prothrombin B, a membrane structure was formed, embedding VEGF and exhibiting delayed release function. METHODS： All rabbits were induced 1-cm animal models with radius defect, and randomly divided into 3 groups, namely VEGF/n-HA group, n-HA group and HA control group, with 20 rabbits in each group. MAIN OUTCOME MEASURES： The vascularization and bone formation of artificial bone implanted into the defect area were evaluated by gross observation, X-ray, histological and immunohistochemical analysis at 2, 4, 8 and 12 weeks postoperatively. RESULTS： Sixty rabbits were involved in the result analysis. Results of X-ray and histology demonstrated the bone formation at each time point of VEGF/n-HA group was significantly higher compared to the n-HA group and HA control group （P 〈 0.05）. Immunohistochemical analysis substantiated that, new bone formation is clearly detectable in the VEGF/n-HA group and HA control group, and the former one was superior to the latter one regarding the vascularization and formation, thus indicating better ability of the defect repairs. CONCLUSION： VEGF has good function to promote early vascularization of the n-HA and improve the repair of bone defects.