构建组织工程骨修复兔颅骨极限缺损的实验研究

EXPERIMENTAL STUDY ON REPAIR OF CRITICAL-SIZED CRANIAL DEFECT BY TISSUE ENGINEERED BONE

目的观察以胶原缓释重组人骨形成蛋白2(recom b inan t hum an bone m orphogenetic prote in 2,rhBM P-2)复合骨髓间充质干细胞(m arrow m esenchym a l stem ce lls,M SC s)及珊瑚构建的组织工程骨修复兔颅骨极限缺损的能力。方法新西兰大白兔40只,制备颅骨极限缺损,按植入的修复物不同随机分为5组,每组8只。Ⅰ组:自体髂骨,为阳性对照组;Ⅱ组:珊瑚,为阴性对照组;Ⅲ组:rhBM P-2+珊瑚;Ⅳ组:胶原+rhBM P-2+珊瑚;Ⅴ组:M SC s+胶原+rhBM P-2+珊瑚。将其分别植入兔颅骨极限缺损处,术后8、16周行大体观察、X线片、HE染色及M asson三色染色法观察比较骨缺损修复的情况。结果术后Ⅴ组材料与Ⅰ组修复颅骨极限缺损的效果相近,缺损区大体标本可见骨样组织充填,硬度与周边骨质相近,并与周边骨质形成明显骨融合;X线阻射程度高,16周时达80.45%±2.52%;组织学观察为板层状结构的新骨组织,空白孔隙区较少。Ⅳ组修复效果次之,Ⅲ组材料成骨能力较弱,Ⅱ组大部为半透明的纤维薄膜,缺损区界限清晰。结论胶原是rhBM P-2适宜的缓释载体,胶原及M SC s对促进复合支架材料修复骨缺损有重要意义。以M SC s+胶原+rhBM P-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。

Objective To evaluate repair of critical-sized cranial defect with tissue engineered bone fabricated by coral, bone mesenchymal stem cells （MSCs） and sustainedly released recombinant human bone morphogenetic protein 2 （rhBMP-2） by collagen. Methods Three scaffolds of rhBMP-2＋coral, collagen＋rhBMP-2＋coral and MSCs＋collagen＋rhBMP-2＋coral were fabricated. Forty New Zealand rabbits were made the models of critical-sized defects and divided into 5 groups according to different implants： group I , auto-ilium; group Ⅱ ,coral; group Ⅲ , rhBMP-2＋coral; grop Ⅳ, collagen＋rhBMP-2＋coral; and group V, MSCs＋collagen＋rhBMP-2＋coral. Repair of bone defect was evaluated after 8 and 16 weeks of implantation by gross obeservation, X-ray, HE staining and Masson＇s trichrome staining. Results Repair of bone defect in group V was similar to that in group I , and was better than that in group Ⅳ ; and group Ⅲ was worse. The gross appearance showed that defect region filled with bony tissue which had similar strength to adjacent bone and formed bone union with surrounding bone. The X-ray result displayed high radiopacity （80.45 % ± 2.52 % in the 16th week）. Histological observation showed new lamellar bone tissue and with few pore blank area. However, only transpasent fibrous tissue filled the defect in group Ⅱ . Conclusion Collagen may be a suitable sustained release system for rhBMP-2. And MSCs may have important effect on enhancing repair of bone defect. Tissue engineered bone fabricated by MSCs＋collagen＋rhBMP-2＋coral may be a useful material for bone defect repair.