三种不同方法制备的硫酸钙片植入修复桡骨节段性骨缺损的实验研究

Restoration of segmental bone defect by calcium sulfate pellet： experiment with rabbits

目的比较3种不同方法制备的硫酸钙片修复兔桡骨节段性骨缺损的效果。方法采用3种经不同方法制备的硫酸钙片修复兔桡骨节段性骨缺损。A组：空白对照组；B组：常规方法制备的硫酸钙组；C组：加压方法制备并经壳聚糖包衣的硫酸钙组；D组：壳聚糖包衣的复合rhBMP-2加压硫酸钙组。术后4、8、12周进行四环素荧光和组织学观察，以及生物力学测试。结果壳聚糖包衣的复合rhBMP-2加压硫酸钙组、壳聚糖包衣的加压硫酸钙组骨缺损愈合，而且前者优于后者。壳聚糖包衣的复合rhBMP-2加压硫酸钙组和壳聚糖包衣的加压硫酸钙组抗弯曲强度高于其他两组，而壳聚糖包衣的复合rhBMP-2加压硫酸钙组又高于壳聚糖包衣的加压硫酸钙组（F=125．3，P〈0．01）。结论壳聚糖包衣的加压硫酸钙片降解时间与新骨形成时间趋于一致，而且抗压强度高，可以修复节段性骨缺损，复合rhBMP-2后可以取得更好的效果。

Objective To compare the effects of different calcium sulfate pellets made by different methods in treating segmental defect of bone. Methods Eighty New Zealand white rabbits underwent cutting off a segment in the middle part of radius so as to establish models of radial segmental defect, and than were divided into 4 groups： Group A as control group, Group B with calcium sulfate pellet made by routine method implanted into the defect, Group C with chitosan coated pressed calcium sulfate pellet implanted into the defect, and Group D with chitosan coated pressed calcium sulfate pellet combined with recombinant human bone morthogenetic protein （rhBMP）-2 implanted into the defect：X-ray photography was done every 4 weeks to observe the new bone formation. Four, 8, and 12 weeks 5 rabbits from each group were killed. The defect segments with parts of normal bone at both ends were cut off to undergo fluorescence microscopy and biomechanic three point bending test. Results X-ray photography and histological examination showed that new bone formation of cortex and reconstruction of marrow cavity were seen in Groups D and C, especially in Group D. The new bone mineralization rate of Group D was significantly higher than that of Group C （P 〈0. 05） which was significantly higher than that of Group B （P 〈0. 01 ）. The anti-bending strength ratio of Group D was （47.5% ±2. 1%, significantly higher than that of Group C [ （39. 6 ± 1.7）% ,F = 125.3 ,P 〈0. 01 ], and the anti-bending strength ratios of Groups D and C were both significantly higher than those of Groups B and A [ （23. 6 ±3. 3）% and （21.3 ±2. 7）% ]. Conclusion Chitosan coated pressed calcium sulfate pellet shows relatively higher anti-bending strength and slightly slower resorption that closely coincide with the growth rate of new bone. It can be used to restore segmental bone defect, and particularly when combined with rhBMP-2.