多孔钛合金表面镁涂层改性及其成骨效应的实验研究

Surface modification of porous titanium alloy by magnesium coating and its effect on bone formation

目的 探讨多孔钛合金表而镁涂层改性材料的制备方法及其成骨效应. 方法 采用真空离子镀技术在多孔钛合金材料内、外表面制备镁金属涂层.扫描电镜观察材料表面及孔隙内部涂层形态,能谱分析涂层的元素组成.取成年家兔24只,随机分为2组（n=12）,建立双侧股骨外侧髁部骨缺损模型,分别植入未涂层的多孔钛合金（对照组）和镁涂层多孔钛合金（实验组）,于取材前2周及前2d分别荧光标记骨小梁.术后2、4、8周取材,应用显微CT检测成骨情况,硬组织切片荧光显微镜观察骨小梁的生长速率,Van Gieson染色后光镜下观察材料周围的成骨情况. 结果 电镜下镁涂层致密且形态规则,与材料表面结合良好,能谱分析显示镁元素存在于材料表面.显微CT结果显示：术后4、8周实验组的新生骨体积百分比平均分别为7.81％ ±1.21％、16.83％±2.39％,均显著高于对照组（5.38％±0.75％、12.08％±1.58％）,差异有统计学意义（P＜0.05）.荧光双标的骨小梁染色结果显示：术后4、8周实验组材料周围双标骨小梁之间的距离平均分别为（49.96 ±5.34）、（67.25±6.75） μm,均显著大于对照组[（26.08±3.64）、（34.69±8.71） μm],差异有统计学意义（P＜0.05）.组织学结果显示：术后4、8周实验组材料新生骨面积百分比平均分别为9.37％±1.66％、16.51％±3.06％,均显著大于对照组（6.70％±0.79％、l2.1 8％±2.44％）,差异有统计学意义（P＜0.05）.结论 多孔钛合金表面镁涂层改性处理对多孔材料内部的骨长人和骨修复具有明显的促进作用.

Objective To investigate the osteogenic ability of porous titanium alloy with its surface modified by magnesium coating.Methods Porous titanium allov （PTA） was coated with magnesium by vacuum ion plating.Surface morphology of PTA scaffolds was observed by scanning electron microscopy （SEM） for analysis of elements of the scaffolds by energy disperse spectroscopy （EDS）.Twenty-four rabbits were used to create models of bone defects of lateral condyle femur at both femurs and randomized into 2 even groups （n =12）.PTA scaffolds were implanted into the defects in the control group while modified PTA scaffolds in the experimental group.Tetracyeline and calcein were injected into the animals at 2 weeks and 2 days before specinens were harvested at 2,4 and 8 weeks postoperation for Micro-CT and histomorphology observations of bone formation,growth rate of bone trabeculae and osteogenesis around the experimental materials.Results SEM revealed the dense and regular magnesium coating attached the matrix very.well.EDS showed the scaffolds were coated with magnesium.Micro-CT revealed that the volumes of bone regeneration in the experimental group at 4 weeks and 8 weeks （7.81% ± 1.21% and 16.83% ± 2.39%） were significantly higher than those in the control group （5.38% ± 0.75% and 12.08% ± 1.58%） （P 〈 0.05）.Fluorescent labeling revealed that the distances between the labeling bone trabeculae around the material in the experimental group at 4 weeks and 8 weeks （49.96 ± 5.34 μm and 67.25 ± 6.75 μm） were significantly longer than those in the control group （26.08 ±3.64 μm and 34.69 ±8.71 μm） （P 〈 0.05）.The histomorphology （Van Gieson staining） revealed that the percentages of bone regeneration in the experimental group at 4 weeks and 8 weeks （9.37% ± 1.66% and 16.51% ±3.06%） were significantly larger than those in the control group （6.70% ± 0.79% and 12.18% ± 2.44%） （P 〈 0.05）.Conclusion Compared with porous titanium scaffolds,the magnesium-coated porous titanium scaffolds possess a better capacity of osteoconductivity and osteogenesis.