羟基磷灰石和二氧化锆梯度复合生物材料修复犬骨缺损

Gradient biocomposite with hydroxyapatite/zirconia for repair of cyno-bone defects

目的评价羟基磷灰石（hydroxyapatite，HA）、二氧化锆（zirconia，ZrO2）梯度复合材料与骨界面的结合情况及修复骨缺损的能力。方法在24只Beagle犬腰椎椎体制作骨缺损模型，依次植入HA／ZrO：梯度复合材料（A组）、HA／ZrO2单层复合材料（B组）、单纯ZrO2材料（c组）、单纯HA材料（D组），分别于术后6，12，16周分批处死动物取材，6，12周处死动物前肌肉注射盐酸四环素行荧光标记，并通过x线片、组织形态学、生物力学测试，观察其界面结合及骨缺损修复情况。结果x线片显示A组随着植入时间的延长，骨痂生成较多，骨修复愈合较好，其次为B组和D组，C组相对较差。组织形态学观察结果显示，6～12周A组材料的荧光标记逐渐增强，并从材料的边缘向材料内部长入，且与材料结合紧密，提示成骨活跃，新骨生成量较多。而B、C、D组材料的荧光标记均集中在材料的边缘，材料内部未见荧光标记。6，12周时四种材料的矿化率差异均有统计学意义（P〈0．05），骨性结合率在6，12，16周时均以A组为最高，16周时达（90．26±3．82）％（P〈0．05）。生物力学测试结果显示，6，12，16周时四组材料的最大抗剪切强度均以A组最大，分别为（2．64±0．16）MPa、（2．95±0．19）MPa、（3．45±0．23）MPa（P〈0．05）。结论HA／ZrO2梯度复合材料与骨界面结合良好，具有较强的骨缺损修复能力，是一种理想的新型骨缺损修复材料。

Objective To evaluate the bonding condition of hydroxyapatite （HA）/zirconia （ ZrO2 ） composite and bone interface and the ability of HA/ZrO2 in repair of bone defects. Methods Bone defect models were established in the lumbar vertebral body of 24 Beagle dogs and were implanted with HA/ZrO2 gradient composite （Group A）, HA/ZrO2 unilayer composite （Group B）, pure ZrO2 （Group C） and pure HA （Group D） successively. Dogs were sacrificed and lumbar vertebral specimens were harvested 6, 12, 16 weeks postoperatively and before the sacrifice at postoperative 6 and 12 weeks, the dogs were intramuscularly administered of quadracycline for fluorescence labeling. The interface bonding and repair of bone defects were observed through X-ray films, histomorphology and biomeehanieal test. Results The X-ray films displayed that the Group A achieved more formation of osteotylus and better repair of bone defects with the extension of the implantation period, followed by the Groups B and D and that the Group C had relatively worse results. Histomorphology study showed that the fluorescence la- beling was enhanced gradually from 6 to 12 weeks in the Group A, with its growth from the edge of the implanted material to the inner part and its tight adhesion to the material, indicating active osteogenesis and massive bone formation. While the fluorescence labeling of the Groups B, C and D centered in the edge of implanted materials without presence in the material inner part. The mineralization rate of the four materials at 6 and 12 weeks had significant differences （P 〈0.05）. Synostosis rates at 6, 12 and 16 weeks were the highest in the Group A, with the rate of up to （90.26 ± 3.82） % at 16 weeks （ P 〈 0.05 ）.Biomechanical test showed the maximum shear strengths at 6, 12, 16 weeks in the Group A were （2.64±0.16） MPa, （2.95±0.19） MPa and （ 3. 45 ±0. 23 ） MParespectively （P〈0.05）. Conclusion HA/ZrO2 gradient biocomposite bonds well with the bone and possesses good repair ability for bone defects and hence is an ideal novel material for bone defect reconstruction.