Qu Tiejun, Jing Junjun, Ren Yinshi, Ma Chi, Feng Jian Q, Yu Qing, Liu Xiaohua
Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, Dallas, TX 75246, United States; State Key Laboratory of Military Stomatology, Department of Operative Dentistry & Endodontics, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, Dallas, TX 75246, United States; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Acta Biomater. 2015 Apr;16:60-70. doi: 10.1016/j.actbio.2015.01.029. Epub 2015 Jan 30.
Dental caries is one of the most prevalent chronic diseases in all populations. The regeneration of dentin-pulp tissues (pulpodentin) using a scaffold-based tissue engineering strategy is a promising approach to replacing damaged dental structures and restoring their biological functions. However, the current scaffolding design for pulpodentin regeneration does not take into account the distinct difference between pulp and dentin, therefore, is incapable of regenerating a complete tooth-like pulpodentin complex. In this study, we determined that scaffolding stiffness is a crucial biophysical cue to modulate dental pulp stem cell (DPSC) differentiation. The DPSCs on a high-stiffness three-dimensional (3D) nanofibrous gelatin (NF-gelatin) scaffold had more organized cytoskeletons and a larger spreading area than on a low-stiffness NF-gelatin scaffold. In the same differentiation medium, a high-stiffness NF-gelatin facilitated DPSC differentiation to form a mineralized tissue, while a low-stiffness NF-gelatin promoted a soft pulp-like tissue formation from the DPSCs. A facile method was then developed to integrate the low- and high-stiffness gelatin matrices into a single scaffold (S-scaffold) for pulpodentin complex regeneration. A 4-week in vitro experiment showed that biomineralization took place only in the high-stiffness peripheral area and formed a ring-like structure surrounding the non-mineralized central area of the DPSC/S-scaffold construct. A complete pulpodentin complex similar to natural pulpodentin was successfully regenerated after subcutaneous implantation of the DPSC/S-scaffold in nude mice for 4weeks. Histological staining showed a significant amount of extracellular matrix (ECM) formation in the newly formed pulpodentin complex, and a number of blood vessels were observed in the pulp tissue. Taken together, this work shows that modulating the stiffness of the NF-gelatin scaffold is a successful approach to regenerating a complete tooth-like pulpodentin complex.
龋齿是所有人群中最普遍的慢性疾病之一。使用基于支架的组织工程策略再生牙本质 - 牙髓组织（牙髓牙本质）是一种有前景的方法，可用于替代受损的牙齿结构并恢复其生物学功能。然而，目前用于牙髓牙本质再生的支架设计没有考虑到牙髓和牙本质之间的明显差异，因此无法再生出完整的牙齿样牙髓牙本质复合体。在本研究中，我们确定支架刚度是调节牙髓干细胞（DPSC）分化的关键生物物理线索。与低刚度的纳米纤维明胶（NF - 明胶）支架相比，在高刚度的三维（3D）纳米纤维明胶支架上的DPSC具有更有序的细胞骨架和更大的铺展面积。在相同的分化培养基中，高刚度的NF - 明胶促进DPSC分化形成矿化组织，而低刚度的NF - 明胶则促进DPSC形成软的牙髓样组织。然后开发了一种简便的方法，将低刚度和高刚度的明胶基质整合到单个支架（S - 支架）中，用于牙髓牙本质复合体的再生。为期4周的体外实验表明，生物矿化仅发生在高刚度的周边区域，并在DPSC / S - 支架构建体的非矿化中心区域周围形成环状结构。将DPSC / S - 支架皮下植入裸鼠4周后，成功再生出了类似于天然牙髓牙本质的完整牙髓牙本质复合体。组织学染色显示，在新形成的牙髓牙本质复合体中有大量细胞外基质（ECM）形成，并且在牙髓组织中观察到了许多血管。综上所述，这项工作表明调节NF - 明胶支架的刚度是再生完整牙齿样牙髓牙本质复合体的成功方法。
