解离的小鼠牙胚上皮细胞在重聚发育过程仍维持牙齿发育基因的表达

Dissociated mouse tooth germ epithelial cells retain the expression of tooth developmental genes during reaggregation process

摘要:

为了解牙胚细胞解离重聚过程的细胞形态和分子机制，将小鼠帽状期牙胚解离细胞重聚，移植到小鼠肾囊膜下培养，组织切片，HE染色，观察再生牙齿的形态发生过程，并用原位杂交的方法进一步检测了与牙上皮发育密切相关的基因在再生牙上皮中的表达情况。结果发现，解离重聚的牙胚细胞在牙齿器官的再生过程重现了正常牙齿的形态发生过程；解离的牙上皮细胞在重聚和再生过程中保持Fgf8、Noggin和Shh等牙上皮发育基因表达。以上结果表明，即便是被解离形成分散状态的牙上皮细胞，在与牙胚间充质细胞重新聚合后，仍保持牙向分化的潜能。该结果为理解牙齿再生的机理提供新的实验数据，对利用干细胞进行牙齿再生的研究有重要的提示意义。

Abstract:

Generation of bio-engineered teeth by using stem cells will be a major approach for bioengineered implantation. Previous studies have demonstrated that dissociated tooth germ cells are capable of generating a tooth after reaggregation in vitro. However, the cellular and molecular mechanisms underlying this tooth regeneration are not clear. In this study, we dispersed E13.5 molar germ into single cells, immediately reaggregated them into cell pellet, then grafted the reaggregates under mouse kidney capsule for various times of culture. We investigated the morphogenesis and the expression of several developmental genes in dental epithelial cells in reaggregates of tooth germ cells. We found that dissociated tooth germ cells, after reaggregation, recapitulated normal tooth developmental process. In additon, dissociated dental epithelial cells retained the expression of Fgf8, Noggin, and Shh during reaggregation and tooth regeneration processes. Our results demonstrated that, despite of under dissociated status, dental epithelial cells maintained their odontogenic fate after re-aggregation with dental mesenchymal cells. These results provided important information for future in vitro generation of bio-engineered teeth from stem cells.