血管内皮祖细胞对组织工程骨成骨能力影响的实验研究

目的观察血管内皮祖细胞（EPCs）时组织工程骨修复兔桡骨大段骨缺顿时成骨能力的影响。方法自体骨髓通过不同方法的体外培养，获得EPCs厦经成骨诱导的MSCs，与DBM构建组织工程骨修复兔桡骨大段骨缺损。观察术后不同时期的影像学及骨密度改变。结果术后2周，EPCs组与对照组的X线观察厦骨密度差异无统计学意义。术后4、8、12周，EPCs组的骨密度明显高于对照组，X线示EPCs组骨痂明显多于对照组，8周可见EPCs组髓腔部分再通，对照组髓腔尚封闭。12周EPCs组新生骨密度均匀，髓腔已完全再通，对照组新生骨仍可见部分低密度区，髓腔大部分再通。术后16周，两组骨密度差异无统计学意义，X线示EPCs组新生骨已基本完成塑形，对照组髓腔完全再通，新生骨处于重建塑形期。结论EPCs可以促进组织工程骨修复大段骨缺损时的成骨能力，加速骨愈合。

An experimental study on effects of bone forming ability of endothelial progenitor cells with tissue engineering bone in repairing segmental defects of rabbit radius

Objective To investigate the effects of endothelial progenitor cells(EPCs)on the bone forming ability of tissue engineering bone during rabbit radius segmental defect healing.Methods The bone marrow mesenchymal stem cells(MSCs)and EPCs of the same rabbits were harvested from bone marrow and cultured in different conditions in vitro.They were seeded on decalcified bone matrix(DBM)to be tissue engineering bone,then implanted into the radius long segmental bone defects of the donor rabbit.The changes of X-ray and bone mineral density(BMD)at the defect site were analyzed at postoperation and the 2nd,4th,8th and 16th week after operation to evaluate the healing of the bone defects.Results There were no difference of X-ray and BMD at 2nd week after operation between EPCs group and control group.But at the 4th,8th and 12th week,the BMD was significantly higher in EPCs group than that in control group.X-ray showed that the callus was much more in EPCs group.From the 8th week,the bone marrow cavity could be seen in EPCs group but not in MSCs group.At the 12th week,the BMD of new bone was well proportioned and the bone marrow cavity re-opened completely in EPCs group.While in control group,some low density area could be seen in X-ray and most of the bone marrow cavity re-opened.At the 16th week,BMD had no significant difference between EPCs group and control group,X-ray showed the new bone had finished reconstruction in EPCs group.While the bone marrow cavity re-opened completely and new bones were reconstructing in control group.Conclusion EPCs can improve bone forming ability of tissue engineering bone in repairing segmental bone defect.