Abstract:

Objective    To explore the feasibility of regenerating mandibular condyles based on cartilage cell sheet with cell bone phase scaffold compared with cell-biphasic scaffolds. Methods    Tissue-engineered mandibular condyles were regenerated by： 1） cartilage cell sheet+bone phase scaffold （PCL/HA） seeded with bone marrow stem cells （BMSCs） from mini-pigs （cell sheet group）， and 2） cartilage phase scaffold （PGA/PLA） seeded with auricular chondrocytes + bone phase scaffold seeded with BMSCs from mini-pigs （biphasic scaffold group）. They were implanted subcutaneously in nude mice after being cultured in vitro for different periods of time. After 12 weeks，  the nude mice were sacrificed，  the specimens were harvested and evaluated based on gross appearance and histopathologic observations with hematoxylin and eosin，  safranin O-fast green and immumohistochemical staining for collagen I and II. The histopathologic assessment score of condylar cartilage and bone density were compared between the 2 groups using SPSS 17.0 software. Results    The two groups′ specimens all formed mature cartilage-like tissues with numerous chondrocytes， typical cartilage lacuna and abundant cartilage-specific extracellular matrix. The regenerated cartilage was instant， continuous， homogeneous and avascular. In the biphasic scaffold group， there were still a few residual PGA fibers in the cartilage layer. The cartilage and bone interface was established in the 2 groups， and the microchannels of the bone phase scaffolds were filled with bone tissue. The score of cartilage regeneration in the cell sheet group was a little higher than the biphasic scaffold group， but without significant difference （P > 0.05）. The number of cartilage cell per unit in cell sheet group was more than that in biphasic scaffold group，but there was no statistical difference（P > 0.05）. There was no significant difference of bone tissue formation between the 2 groups （P > 0.05）. BMSCs near cartilage phase differentiated to cartilage，while those far from it differentiated to bone tissue and adipose tissue. Conclusion    Both cartilage cell sheet group and biphasic scaffold group can regenerate condyle shaped osteochondral composite in nude mice. Without residual PGA fibers， the cell sheet group has less chance of immunological rejection and has wider application in the future.

Key words: temporomandibular joint, regeneration, condyle, nude mouse

摘要：

目的    探讨不同复合材料构建的生物髁突在裸鼠皮下再生的可行性。方法    分别采用软骨细胞膜片+骨相支架（PCL/HA）复合骨髓间充质干细胞（BMSCs）（细胞膜片组），以及软骨相支架（PGA/PLA）复合耳软骨细胞+骨相支架细胞复合BMSCs（双相支架组）体外构建具有三维组织形态的生物髁突，经体外分别培养不同时间后将软骨相复合物和骨相复合物缝合在一起后植入裸鼠皮下，12周后处死并取材。分别进行组织学和免疫组化染色，对再生的软骨组织、骨组织以及骨软骨交界面进行评价。结果    在裸鼠体内，细胞膜片组和双相支架组的软骨相修复体形成了类似成熟的软骨组织，可见大量的软骨细胞、典型的软骨陷窝和丰富的软骨基质，形成的软骨完整、连续、均质、无血管。双相支架组软骨层中仍有少量未降解的复合材料纤维。2组的软骨相修复体和骨相修复体都能够通过组织连接紧密结合在一起；骨相支架空隙内都有软骨组织以及少量的骨组织和脂肪组织形成。细胞膜片组的软骨修复组织学评分高于双相支架组，但差异无统计学意义（P＞0.05）。软骨膜片组的每单位软骨细胞数量多于双相支架组，但差异亦无统计学意义（P＞0.05）。骨相组织成骨2组类似，离软骨相修复体近的BMSCs向软骨分化，离软骨相修复体远的BMSCs向骨组织和脂肪组织分化。结论    软骨细胞膜片复合骨相细胞支架，以及软骨-骨细胞复合双相支架均能够在裸鼠皮下成功构建生物髁突；软骨细胞膜片复合骨相支架再生的生物髁突在具备完善免疫力的哺乳动物体内更具有应用前景。

关键词: 颞下颌关节, 再生, 生物髁突, 裸鼠