低温保存的组织工程骨修复骨缺损的实验研究

目的探讨低温保存的组织工程骨修复骨缺损的能力及低温保存的可行性。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。80只成年日本大耳白兔,随机分为4个实验组(左前肢植入材料):A3组:组织工程骨在4℃保存3个月;A6组:组织工程骨在4℃保存6个月;B3组:组织工程骨在-196℃保存3个月;B6组:组织工程骨在-196℃保存6个月。2个对照组(右前肢植入材料):C组:组织工程骨未行低温保存;D组:单纯生物衍生骨材料。于术后2、4、6和12周行大体和组织学观察,并于6周和12周行X线片检查和生物力学检测。结果术后大体观察,A3、A6、B3、B6和C组间无显著差异,D组骨痂少且断端更为明显。各时间点组织学观察,A3、A6、B3、B6和C组植入材料周围胶原及骨痂均较D组明显,术后12周组织学评分,D组与其它各组比较P值<0.05。X线片示D组植入材料皮质骨无明显变化,骨痂较少;余各组12周植入材料与自体骨融合,髓腔开通,骨折线消失,塑形好。生物力学检测D组与其它各组比较P值<0.05。结论以4℃和-196℃保存方法能有效保存组织工程骨,对修复骨缺损有明显效果,这一方法适宜推广应用。

EXPERIMENTAL STUDY OF TISSUE ENGINEERED BONE WITH CRYOPRESERVATON ON HEALING OF BONE DEFECTS

OBJECTIVE: To investigate the effect of tissue engineered bone with cryopreservation on healing of bone defects and to explore feasibility of cryopreservation for tissue engineered bone. METHODS: Tissue engineered bones were constructed with osteoblasts being seeded onto bio-derived materials made from fresh human bones,and they were preserved at 4 degrees C and - 196 degrees C for 3 months and 6 months respectively. They were applied to repair segmental bone defects of rabbit's radius while the tissue engineered bone without cryopreservation and bio-derived materials were brought into control groups. The experiment was divided into groups A3, A6, B3, B6, C and D (group A3: tissue engineered bones were preserved at 4 degrees C for 3 months; group A6: tissue engineered bones were preserved at 4 degrees C for 6 months; group B3:tissue engineered bones were preserved at --196 degrees C for 3 months; group B6:tissue engineered bones were preserved at - 196 degrees C for 6 months; group C: tissue engineered bones without cryopreservation; group D: bioderived materials). Macroscopical and histologial examination were done at the 2nd, 4th, 6th, 12th weeks, X-ray examination was done at the 6th, 12th weeks and biomechanics were determined at 12th weeks after operation respectively. RESULTS: Macroscopical observation showed no significant differences among group A3, A6, B3, B6 and C, but less new bone formation and more obvious boundary in group D were observed. Histological observation showed more collagen and new bone around the edge of implant of group A3, A6, B3, B6 and C than group D, and histological evaluation showed significant differences between group D and other groups (P <0.05). Radiographic observation showed no absorbability of the implant cortex and less new bone formation in group D, but the unity between implant and host bone, medullary cavity reopened, disappearance of fracture line and fine bone modelling were observed in other groups at 12 weeks after operation. Biomechanics between group D and other groups showed significant differences (P< 0. 05). CONCLUSION: Cryopreservation (4 degrees C and - 196 degrees C) were capable of preserving tissue engineered bone for long time, and tissue engineered bone with cryopreservation has significant effect on healing of bone defects. The methods fit clinical application.