Department of Restorative Dentistry and Periodontology, University of Regensburg, Regensburg, Germany.
J Endod. 2011 Nov;37(11):1536-41. doi: 10.1016/j.joen.2011.08.027.
Recent successes in dental pulp engineering indicate that regenerative treatment strategies in endodontics are feasible. Clinically, revascularization procedures render completion of root formation in immature teeth. The generation of a pulp-like tissue after seeding of dental pulp stem cells into dentin discs or cylinders and transplantation in vivo is possible. In this experimental setup, which mimics the situation in the root canal, the pretreatment of dentin might influence cellular behavior at the cell-dentin interface. Thus, the objective of this study was to investigate whether dentin conditioning can determine cell fate.
Dental pulp stem cells (DPSCs) were seeded into a growth factor-laden peptide hydrogel, transferred into dentin cylinders, and transplanted subcutaneously into immunocompromised mice. Before cell seeding, dentin cylinders were either pretreated with sodium hypochloride (NaOCl) or conditioned with EDTA. The constructs were explanted after 6 weeks and subjected to histological and immunohistochemical analysis.
In dentin treated with NaOCl, resorption lacunae were found at the cell-dentin interface created by multinucleated cells with clastic activity. After conditioning with EDTA, DPSCs adjacent to the dentin formed an intimate association with the surface, differentiated into odontoblasts-like cells that expressed dentin sialoprotein, and extended cellular processes into the dentinal tubules. A vascularized soft connective tissue similar to dental pulp was observed inside the dentin cylinder.
Dentin conditioning considerably influences DPSC fate when seeded in close proximity to dentin. This information might be critical for optimized strategic planning for future regenerative endodontic treatment.
最近牙髓工程的成功表明，牙髓内再生治疗策略是可行的。临床上，血运重建程序可使未成熟牙齿的牙根继续形成。将牙髓干细胞种植于牙本质片或牙本质圆柱内，并移植到体内，可产生类似于牙髓的组织。在这个实验模型中，模拟了根管内的情况，牙本质的预处理可能会影响细胞-牙本质界面的细胞行为。因此，本研究旨在探讨牙本质预处理是否可以决定细胞的命运。
将牙髓干细胞（DPSCs）接种到富含生长因子的肽水凝胶中，转移到牙本质圆柱内，并移植到免疫缺陷小鼠的皮下。在细胞接种之前，牙本质圆柱用次氯酸钠（NaOCl）预处理或用 EDTA 处理。6 周后将构建体取出，进行组织学和免疫组织化学分析。
在用 NaOCl 处理的牙本质中，在具有破骨活性的多核细胞形成的细胞-牙本质界面处发现了吸收腔隙。经 EDTA 处理后，与牙本质相邻的 DPSCs 与表面形成紧密联系，分化为表达牙本质涎蛋白的成牙本质细胞样细胞，并将细胞突起延伸到牙本质小管内。在牙本质圆柱内观察到类似于牙髓的血管化软结缔组织。
当将牙髓干细胞种植到牙本质附近时，牙本质预处理会极大地影响其命运。这些信息对于未来再生性牙髓治疗的优化策略规划可能至关重要。
