组织工程骨低温保存后修复兔骨缺损的影像及形态学分析

Radiographic and morphological studies on tissue engineered bone after cryopreservation in repairing rabbit bone defects

目的探讨低温保存的组织工程骨修复兔骨缺损的能力以及低温保存组织工程骨的可行性。方法将人源性生物衍生骨材料复合成骨细胞构建的组织工程骨,在4℃和-196℃的温度环境中保存3个月和6个月,同时以未行低温保存的组织工程骨和生物衍生骨材料作为对照,分别修复实验兔桡骨的长段骨缺损,于术后2、4、6、12周时行大体和组织学观察,并于6、12周行X线检查。结果4℃和-196℃的温度保存组和未行低温保存的组织工程骨组在动物体内相同时间点影像学和形态学观察无明显区别,低温保存3个月与6个月组在动物体内相同时间点影像学和形态学无明显区别;组织工程骨各组与单纯生物衍生骨材料组比较,前者在骨缺损处产生更多的胶原与新骨,其修复骨缺损是通过多点方式成骨,成骨迅速,骨愈合更快;而单纯生物衍生骨材料组从两端“爬行替代”方式成骨;所有各组无明显排斥反应。结论本研究采用的低温(4℃和-196℃)保存方法均能有效保存组织工程骨,从影像学和形态学研究证实该保存方法是有效可行的。

Objective To investigate the effects of cryopreserved tissue engineered bone on healing of rabbits bone defects and to explore the feasibility of cryopreservation of tissue engineered bone. Methods Osteoblasts were seeded onto bio-derived materials made from fresh human bones to construct the tissue engineered bones. Next after the bones were preserved at 4℃ and -196℃ for 3 months and 6 months respectively, they were applied to repair segmental bone defects at radius of rabbits. At the same time the contrast experiments were done using the tissue engineered bones without cryopreservation or bio-derived materials in the control groups. Macroscopical and histological examinations were done at the 2nd, 4th, 6th, and 12th weeks, while X-ray examination was done at the 6th and 12th weeks after operation respectively. Results Radiographic and morphological observations showed that there were no significant differences between tissue engineered bones with cryopreservation (4℃ and -196℃) and tissue engineered bones without cryopreservation, and no significant differences between cryopreservation for 3 months and for 6 months. Compared with the group of bio-derived materials in which the bone defects were repaired in a ‘creeping substitution' way, the bone defects in the groups of tissue engineered bone with and without cryopreservation were repaired in a ‘multipoint' way, and collagen and new bone occurred more and earlier. No obvious immunological rejection reaction could be seen in all the groups. Conclusion Cryopreservation (4℃ and -196℃) is a feasible and effective way to preserve tissue engineered bones for a long time.