目的 应用骨髓间充质干细胞(BMSCs)细胞片层构建组织工程骨修复犬下颌骨缺损,探讨细胞片层在成骨中的作用.方法 采用密度梯度离心法分离和培养BMSCs,将BMSCs向成骨细胞诱导培养后,制备细胞片层.将细胞片层包裹到聚乳酸羟基乙酸共聚物(PLGA)支架表面,将其植入犬左侧下颌骨全层缺损中,对侧下颌骨植入无细胞片层包裹的支架复合体作同体对照.将16只犬分为4组,每组4只.术后4、8、12、16周分别处死1组,取材行大体及组织学观察.结果 实验侧成骨好于对照侧,术后16周,实验侧骨缺损大部分被新生骨替代,舌侧形成与正常骨相似的密质骨,与正常骨断端骨性愈合.实验侧新生骨光密度值大于对照侧,两者差异有统计学意义(P＜0.05).实验侧可见较多哈弗氏系统及红骨髓,大量板层骨；对照侧哈弗氏系统较少.结论利用细胞片层技术可以构建出含板层骨结构的组织工程骨.%Objective To reconstruct mandibular defect using tissue engineering bone with bone mam? Stem cells (BMSCs) ceil sheets and investigate the effect of cell sheets on osteogeneeis. Methods BMSCs were isolated with the method of density gradient centrifugation from canine and cultured. BMSCs were induced to differentiate to osteo-blasts. BMSCs induced were fabricated to BMSCs cell sheets. The poly Qactic-co-glyeolic acid) (PLGA) wrapped with cell sheets were implanted into the mandibular defect in the left side (experimental side). PLGA wrapped without cell sheets were implanted into the right side (control side) of mandibles. 16 dogs were evenly divided into 4 groups, and one group of them was executed in 4, 8, 12. 16 weeks for gross investigation and histological observation. Results The osteogenesis of experimental side was better than that of control side. 16 weeks after implantation, most areas of the mandibular defect were replaced by fresh bone tissue. Compact bone similar to normal bone tissue formed in the lingual defect of mandible and had bony union with the bone stump. The optical density of the fresh bone in the experimental side was higher than that of the control side, there was a significant difference between the two methods (P<0.05). Plenty of lamellar bones formed in experimental side and Haversian system, as well as red marrow, were observed Conclusion Tissue engineering bone with the structure of lamellar bones can be formed by the technology of BMSCs cell sheets.
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