Department of Craniofacial Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT, USA.
Bone. 2010 Jun;46(6):1639-51. doi: 10.1016/j.bone.2010.02.019. Epub 2010 Feb 26.
In the past few years there have been significant advances in the identification of putative stem cells also referred to as "mesenchymal stem cells" (MSC) in dental tissues including the dental pulp. It is thought that MSC in dental pulp share certain similarities with MSC isolated from other tissues. However, cells in dental pulp are still poorly characterized. This study focused on the characterization of progenitor and stem cells in dental pulps of erupted and unerupted mice molars. Our study showed that dental pulps from unerupted molars contain a significant number of cells expressing CD90+/CD45-, CD117+/CD45-, Sca-1+/CD45- and little if any CD45+ cells. Our in vitro functional studies showed that dental pulp cells from unerupted molars displayed extensive osteo-dentinogenic potential but were unable to differentiate into chondrocytes and adipocytes. Dental pulps from erupted molars displayed a reduced number of cells, contained a higher percentage of CD45+ and a lower percentage of cells expressing CD90+/CD45-, CD117+/CD45- as compared to unerupted molars. In vitro functional assays demonstrated the ability of a small fraction of cells to differentiate into odontoblasts, osteoblasts, adipocytes and chondrocytes. There was a significant reduction in the osteo-dentinogenic potential of the pulp cells derived from erupted molars compared to unerupted molars. Furthermore, the adipogenic and chondrogenic differentiation of pulp cells from erupted molars was dependent on a long induction period and were infrequent. Based on these findings we propose that the dental pulp of the erupted molars contain a small population of multipotent cells, whereas the dental pulp of the unerupted molars does not contain multipotent cells but is enriched in osteo-dentinogenic progenitors engaged in the formation of coronal and radicular odontoblasts.
在过去的几年中，人们在鉴定牙组织（包括牙髓）中的所谓干细胞，也称为“间充质干细胞”（MSC）方面取得了重大进展。人们认为牙髓中的 MSC 与从其他组织中分离出的 MSC 具有某些相似之处。然而，牙髓细胞的特征仍然很差。本研究集中于表征萌出和未萌出小鼠磨牙牙髓中的祖细胞和干细胞。我们的研究表明，未萌出磨牙牙髓中含有大量表达 CD90+/CD45-、CD117+/CD45-、Sca-1+/CD45-的细胞，几乎没有 CD45+细胞。我们的体外功能研究表明，来自未萌出磨牙牙髓的牙髓细胞具有广泛的成骨牙本质形成潜力，但不能分化为软骨细胞和成脂细胞。萌出磨牙的牙髓显示细胞数量减少，CD45+细胞百分比增加，CD90+/CD45-、CD117+/CD45-表达的细胞百分比降低。与未萌出磨牙相比，体外功能测定显示一小部分细胞具有分化为成牙本质细胞、成骨细胞、脂肪细胞和软骨细胞的能力。萌出磨牙的牙髓细胞的成骨牙本质形成潜力与未萌出磨牙相比显著降低。此外，萌出磨牙牙髓细胞的成脂和成软骨分化依赖于较长的诱导期，且频率较低。基于这些发现，我们提出萌出磨牙的牙髓含有一小部分多能细胞，而未萌出磨牙的牙髓不含多能细胞，但富含参与形成冠根成牙本质细胞的成骨牙本质祖细胞。
