Liu Guangpeng, Zhao Li, Zhang Wenjie, Cui Lei, Liu Wei, Cao Yilin
Shanghai Tissue Engineering Research and Development Center, Shanghai, 200235, China.
J Mater Sci Mater Med. 2008 Jun;19(6):2367-76. doi: 10.1007/s10856-007-3348-3. Epub 2007 Dec 25.
Tissue engineering techniques have been proven effective in bone regeneration and repairing load-bearing bone defects. Previous studies, however, have heretofore been limited to the use of slowdegradable or natural biomaterials as scaffolds. There are, however, no reports on using biodegradable, synthetic beta-tricalcium phosphate (beta-TCP) as scaffolds to repair weight-bearing bone defects in large animals. In the present study, highly porous beta-TCP scaffolds prepared by the polymeric sponge method were used to repair goat tibial defects. Fifteen goats were randomly assigned to one of three groups, and a 26 mm-long defect at the middle part of the right tibia in each goat was created. In Group A (six goats), a porous beta-TCP ceramic cylinder that had been loaded with osteogenically induced autologous bone marrow stromal cells (BMSCs) was implanted in the defect of each animal. In Group B (six goats), the same beta-TCP ceramic cylinder without any cells loaded was placed in the defect. In Group C (three goats), the defect was left untreated. In Group A, bony union can be observed by gross view, X-ray and micro-computed tomography (Micro-CT) detection, and histological observation at 32 weeks post-implantation. The implanted beta-TCP scaffolds were almost completely replaced by tissue-engineered bone. Bone mineral density in the repaired area of Group A was significantly higher (p < 0.05) than that of Group B, in which scant new bone was formed in each defect and the beta-TCP hadn't been completely resorbed at 32 weeks. Moreover, the tissue-engineered bone of Group A had similar biomechanical properties as that of the normal left tibia in terms of bending strength and Young's modulus (p > 0.05). In Group C, little or no new bone was formed, and non-union occurred, showing that the 26 mm segmental defect of the goat tibia was critical sized at 32 weeks. Thus, it can be concluded that the mechanical properties of the BMSCs/beta-TCP composites could be much improved via tissue engineering approach and beta-TCP might be used to repair the weight-bearing segmental defects of goat tibias.
组织工程技术已被证明在骨再生和修复承重骨缺损方面有效。然而，以往的研究仅限于使用缓慢降解的或天然生物材料作为支架。然而，尚无关于使用可生物降解的合成β-磷酸三钙（β-TCP）作为支架修复大型动物承重骨缺损的报道。在本研究中，采用聚合物海绵法制备的高度多孔β-TCP支架用于修复山羊胫骨缺损。15只山羊被随机分为三组，每只山羊右胫骨中部制造一个26毫米长的缺损。A组（6只山羊），将已加载成骨诱导自体骨髓基质细胞（BMSCs）的多孔β-TCP陶瓷圆柱体植入每只动物的缺损处。B组（6只山羊），将相同的未加载任何细胞的β-TCP陶瓷圆柱体置于缺损处。C组（3只山羊），缺损未作处理。在A组，植入后32周通过大体观察、X线和微计算机断层扫描（Micro-CT）检测以及组织学观察可观察到骨愈合。植入的β-TCP支架几乎完全被组织工程骨替代。A组修复区域的骨密度显著高于B组（p<0.05），B组每个缺损处新骨形成很少，且在32周时β-TCP未完全吸收。此外，A组的组织工程骨在弯曲强度和杨氏模量方面与正常左胫骨具有相似的生物力学性能（p>0.05）。在C组，几乎没有形成新骨，出现了骨不连，表明山羊胫骨26毫米节段性缺损在32周时为临界大小。因此，可以得出结论，通过组织工程方法可大大改善BMSCs/β-TCP复合材料的力学性能，且β-TCP可用于修复山羊胫骨的承重节段性缺损。
