复合支架材料构建组织工程骨修复兔颅骨缺损

目的观察以胶原缓释重组人骨形态发生蛋白-2（rhBMP-2）复合骨髓间充质干细胞（BMSCs）及珊瑚构建的组织工程骨修复颅骨缺损的能力，明确复合BMSCs的组织工程骨修复颅骨缺损后新骨的来源。方法构建三种复合支架材料：（1）rhBMP-2／珊瑚；（2）胶原/rhBMP-2／珊瑚；（3）BMSCs／胶原／rhBMP-2／珊瑚。将其分别植入兔颅骨缺损处，8周和16周后采用X线片、HE染色、Masson三色染色法、荧光显微镜等观察比较骨缺损修复的情况。通过BrdU标记BMSCs及免疫组化染色方法证实新骨的来源。结果BMSCs／胶原/rhBMP-2／珊瑚组材料修复颅骨缺损的能力最强，且与自体髂骨修复的情况相近；胶原／rhBMP-2／珊瑚组材料次之，rhBMP-2／珊瑚组材料成骨能力较弱。BMSCs参与了新骨组织的形成，新骨组织部分来源于经诱导的BMSCs。结论胶原是rhBMP-2适宜的缓释载体，胶原及BMSCs对促进复合支架材料修复骨缺损有重要意义。BMSCs／胶原／rhBMP-2／珊瑚构建的组织工程骨可成为一种良好的骨缺损修复材料．

Repair of cranial defect by tissue-engineered bone formed by composite scaffold material in rabbits

Objective To evaluate potential of collagen sustained release recombinant human bone morphogenic protein-2 (rhBMP-2) composed with coral and bone mesenchymal stem cells in repair of cranial defect aiming to clarify the origin of new bone after defect repair by such tissue-engineered bone. Methods We fabricated three scaffolds that were divided into three groups, ie, rhBMP-2/coral group, collagen/rhBMP-2/coral group and BMSCs/collagen/rhBMP-2/coral group. Repair of bone defect was evaluated after implantation of scaffolds into the defect at the 8th and 16th weeks later by means of X-ray, HE stain, Masson's trichrome stain and fluorescent microscope. Negative control group (only coral) and positive control group (iliac bone autoimplantation) were also set. BrdU was added into the cells during cell culture procedure. Immunohistochemical stain method was used to observe expression of BrdU in new bones. Results The bone defect was repaired the best in BMSCs/collagen/rhBMP-2/coral group, which was similar to that in positive control group. Bone formation was better in collagen/rhBMP-2/coral but the least in rhBMP-2/coral group. BMSCs participated in formation of new bone that partly came from the induced BMSCs. Conclusions Collagen may be a suitable sustained release system for rhBMP-2. Meanwhile, collagen and BMSCs may play important role in enhancing repair of bone defects. Tissue-engineered bone fabricated by BMSCs/collagen/rhBMP-2/ coral may be a satisfactory material for bone defect repair.