组织工程化人工骨移植修复长骨干缺损的成骨研究

Osteogenesis in transplantation of tissue engineered bone to repair segmental defect of long bone

目的研究仿生制备的组织工程化人工骨移植修复长骨干缺损的成骨性能、修复效果及可能的修复机制。方法采用人工合成双相羟基磷灰石(HA/β-TCP)为支架材料,与聚-DL-乳酸(PDLLA)复合后再复合Ⅰ型胶原及重组合人类骨形态发生蛋白-2(rhBMP-2),与兔骨膜成骨细胞及肾脏血管内皮细胞复合培养。将仿生制备的组织工程化人工骨移植到日本大耳白兔桡骨完全骨膜-骨缺损区,分别于术后第4、8、12周进行大体解剖观察、X线观察、HE染色及Masson三色法染色组织学观察、图像分析、扫描电镜、X线能谱分析,研究骨缺损的修复情况。结果术后第4周可见新生板层骨;第8周植入物与自体骨呈皮质骨融合,有新骨髓长入;第12周植入物外周被新生皮质骨完全替代,组织学新生骨呈数个连续过渡的条带样分布区。新生骨定量4周组与8周组及12周组比较差异有显著性,8周组与12周组差异无显著性。随植入时间延长,植入体中钙/磷比值趋向于自体皮质骨。结论仿生构建的组织工程化人工骨植入体内修复长骨干缺损,修复效果好,其骨再生机制为软骨内化骨。

Objective To investigate the ability of osteogenesis, repaired effects and possible mechanism of tissue engineered bone made in an approach of bionics as a transplantation biomaterial to repair a segmental defect of long bone. Methods HA/β-TCP was composed with PDLLA and then composed with rhBMP-2 and collagen of typeⅠ. The combined biomaterial was put in common culture with osteoblasts harvested from periosteum of rabbit and vascular endothelial cells from kidney of rabbit then transplanted this tissue engineered bone to total segmental periosteum-bone defect of 1.5 cm in the rabbits radius which were investigated 4, 8 and 12 weeks after operation respectively. Investigation of the bone defect was made by means of gross observation, X-ray examination, histology of HE and Masson staining, image pattern analysis, scanning electron microscopy, EDAX. Results In gross observation, the implantations were adhered to the host bone well in four weeks, the implantations was bony healed with host bone in eight weeks, and some of the implantations were replaced by new formation bone in 12 weeks. In histological examination of four weeks after operation, lamellar bone was found, and eight weeks after operation, implant was incorporated to host bone end by end through cortical bone, and new bone marrow was found to invade into the implant. Furthermore, the outer part of implant was completely substituted by new cortical bone 12 weeks after operation. In addition, the histological study pointed out that the new bone arranged in type of various bands which were in subsequent transition. There is significant difference between 4 weeks and 8 weeks, and 4 weeks and 12 weeks, but no significant difference between 8 weeks and 12 weeks of the quantity of new bone. The ratio of calcium to phosphorus in the transplants tended to approach that in the host cortical bone along with the period of time after operation. Conclusion Satisfied effects of remodeling appeared after this tissue engineered bone composed by bionics was transplanted to the segmental defect of long bone. The mechanism of bone regeneration was endochondral ossification.