不同孔径纳米羟基磷灰石人工骨修复兔桡骨缺损效果比较

Nano-hydroxyapatite artificial bone with different pore sizes to repair radial defect in rabbits

目的:纳米级的羟基磷灰石材料与人体内组织成分更为相似,具有更佳的生物性能。评价不同孔径的多孔纳米羟基磷灰石人工骨的骨缺损修复能力,从而筛选出适合的孔径以达到骨传导功能与生物力学性能的良好统一。方法:实验于2005-10/2006-10在深圳市第二人民医院中心实验室完成。①实验材料:纳米羟基磷灰石人工骨以硝酸钙和磷酸二氢铵为原料,采用溶胶-絮凝法制备粉体,运用压力成型、木模成型和浸渍成型分别制得孔隙分布均匀的孔径分别为50～150μm、100～250μm和300～500μm的多孔纳米羟基磷灰石人工骨。②实验动物:雄性新西兰大白兔60只随机分为植入50～150μm孔径材料组、植入100～250μm孔径材料组、植入300～500μm孔径材料组、空白对照组,每组15只。实验过程中对动物处置符合动物伦理学要求。③实验方法:制备双侧桡骨骨缺损动物模型,然后用3种不同孔径的纳米羟基磷灰石人工骨材料植入骨缺损处进行修复,空白对照组不植入任何材料。④实验评估:术后4,8和12周分别行大体标本观察、X射线片观察、扫描电镜观察及生物力学测试,比较各组材料修复骨缺损的能力。结果:实验动物均进入结果分析。①X射线片检查结果:术后4周、8周、12周,植入100～250μm孔径材料组X射线评分高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。②生物力学检测结果:术后4周、8周、12周,植入100～250μm孔径材料组生物力学强度高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。③扫描电镜观察结果:植入100～250μm孔径材料组成骨效果明显优于植入50～150μm,300～500μm孔径材料组和空白对照组。结论:纳米羟基磷灰石人工骨具有良好的成骨能力,但其骨修复能力受孔径因素的影响,孔径100～250μm的纳米羟基磷灰石人工骨材料成骨能力较好。

AIM： The nano-hydroxyapatite （n-HA） is similar to the human tissues and possesses better biological performance. This paper investigated polyporous n-HA artificial bone with different pore sizes on bone defect＇s reconstruction and screened out a suitable pore size to unify the osteoconductibility and biomechanical performance. METHODS： The experiment was carried out in the Central Laboratory of Shenzhen Second People＇s Hospital from October 2005 to October 2006. （1）The n-HA consisting of calcium nitrate and ammonium dihydrogen phosphate was prepared into powders by using sol-flocculence. Then polyporous n-Ha artificial bones with uniform pore distribution and different pore sizes （50-150 μm, 100-250 μm and 300-500 μm） were prepared by pressure molding, wood pattern forming and dip forming respectively.（2）Animal models of bone defect were established on the bilateral radius of 60 male New Zealand white rabbits, which were randomly divided into three experimental groups （bone defect was repaired with n-HA artificial bone with three kinds of pore size） and bland control group （bone defect was left unrepaired）, with 15 animals in each group. All the disposals accorded with the ethnical standard of animals. （3）The ability of repairing bone defect was evaluated by gross observation, X-ray radiograph, scanning electronic microscope and biomechanical analysis in 4, 8, 12 weeks after operation. RESULTS： All the experimental animals were involved in the result analysis. （1）Radiographical scores of group B was higher than those of group A and group C at 4, 8 and 12 weeks, and the differences were statistically significant between group A and B, group B and C （P 〈 0.05）.（2）At 4, 8 and 12 weeks postoperatively, the biomechanical strengths of group B were stronger than those of group A and C, and the differences were statistically significant （P 〈 0.05）.（3）The materials having pore sizes in the range of 100-250μm stimulated more bone formation than the material with other pore sizes and blank control group. CONCLUSION： The n-HA artificial has good osteoconductibility. Pore size may significantly affect its ability of repairing bone defect. The n-HA artificial bone materials with pore size in range of 100-250μm have better osteoconductibility.