BACKGROUND: The previous methods for the repair of tendon defect include end-to-end method, autologous tendon graft, tendon al ograft or artificial tendon transplantation, but each method has its advantages and disadvantages. OBJECTIVE: To investigate the feasibility of constructing tissue-engineered tendon by rabbit bone marrow mesenchymal stem cells as seed cells which were induced by bone morphogenetic protein 12 and with col agen-polyglycolic acid composite as frameworks in the repair of rabbit tendon defects. METHODS: Bone marrow was separated from rabbit proximal femur to harvest cells, and the cells were passaged to the second generation and induced with 10 μg/L bone morphogenetic protein 12. Then the passage 2 cells were implanted into the prefabricated tissue-engineered tendon on the polyglycolic acid stitch with certain percentage together with col agenⅠsolution. The rabbits were used to establish the Achil es tendon defect models, and different methods were used to repair Achil es tendon defect: tissue-engineered tendon, col agenⅠ-polyglycolic acid stitch and end-to-end suturing in silk. Morphology, mechanics and shistopathology of the tissue-engineered tendon were observed. RESULTS AND CONCLUSION: Pathomorphological observation of histological section after 12 weeks showed that multiple fusiform fibroblasts were homogeneously distributed in col agen in the direction of stress mechanics.Fibrocytes increased obviously, new smal vessels could be seen and col agen was found aligned compactedly. In col agen Ⅰ-polyglycolic acid stitch group, a part of fibroplasia hyperplasia accompanied by granulation tissue formation could be seen, the col age fibers were in loose filamentous network and the cells were distributed disorderly and unevenly. Granulation tissue formed around the fibrous tissue in the silk group. Biomechanics strength in bone morphogenetic protein 12+polyglycolic acid group was better than that in the col agen Ⅰ-polyglycolic acid group, and there was significant difference when compared with suture silk group. The biomechanics strength of the bone morphogenetic protein 12+polyglycolic acid group was lower than that of normal tendon. It is possible to construct a tissue-engineered tendon with autologous bone marrow mesenchymal stem cells as seed cells induced by bone morphogenetic protein 12 and with the col agen-polyglycolic acid as the framework. Constructed tissue-engineered tendon has biomechanics characteristics and can be used to repair Achil es tendon defect.% 背景：以往肌腱损伤的修复方法有端端吻合、自体肌腱移植、同种异体肌腱或人工肌腱移植等，但均有其各自缺点。目的：探讨以家兔骨髓间充质干细胞为种子细胞，骨形态发生蛋白12诱导，聚羟基乙酸复合材料作为支架材料，预构组织工程化肌腱重建家兔跟腱缺损的可能性。方法：家兔抽取股骨近端骨髓，分离所得细胞传代至第2代，加入10μg/L 骨形态发生蛋白12诱导分化，并与Ⅰ型胶原溶液按一定比例移植于预张的聚羟基乙酸缝线上预制组织工程化肌腱备用。将家兔制备成跟腱缺损模型，分别采用不同方法修复跟腱缺损：组织工程化肌腱修复，Ⅰ型胶原-聚羟基乙酸缝线修复，丝线行端端修复。修复12周对各组肌腱行形态学、力学及组织病理学观察。结果与结论：修复12周家兔肌腱组织病理切片：组织工程化肌腱组可见大量梭形纤维母细胞顺应力学方向排列均匀分布于胶原中，纤维细胞明显增多，胶原致密；Ⅰ型胶原-聚羟基乙酸缝线组可见部分纤维组织增生伴少许肉芽组织形成，胶原纤维呈松散网丝状，细胞排列紊乱分布不均；丝线组可见纤维组织旁见大量肉芽组织形成。修复12周家兔肌腱生物力学强度：骨形态发生蛋白12+聚羟基乙酸重建肌腱的力学强度明显优于Ⅰ型胶原-聚羟基乙酸组，与丝线缝合组差异无显著性意义；但骨形态发生蛋白12+聚羟基乙酸重建肌腱的力学强度低于正常肌腱。提示以自体骨髓间充质干细胞作为种子细胞，骨形态发生蛋白12诱导，以聚羟基乙酸为支架，可望构建组织工程化肌腱。构建的组织工程肌腱具有一定的生物力学特性，能用于修复跟腱缺损。
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