Early revascularization activates quiescent dental pulp stem cells following tooth replantation in mice

Introduction: The intentional perforation of the pulp chamber floor before tooth replantation promotes pulpal healing by facilitating the revascularization of the pulp cavity. This study aimed to elucidate the effects of this method on the dynamics of quiescent dental pulp stem cells (DPSCs).Methods: The right and left maxillary first molars of Crlj:CD1 mice and TetOP-histone 2B (H2B)-green fluorescent protein (GFP) mice were extracted. The left molars were immediately replanted as the control group (CG), whereas the pulp chamber floor of the right molars were perforated before the tooth was replanted as the experimental group (EG). Immunohistochemistry for Nestin and GFP, and quantitative RT-PCR for Nestin, Opn, CD11c, and Oct3/4 mRNA were performed.Results: The rate of Nestin-positive perimeter along the pulp-dentin border in the EG tended to be higher than that of the CG at days 5 and 7 and was significantly increased between days 3 and 7. The rate of GFP-positive cells in the EG was significantly higher than that of the CG at days 5 and/or 7 in the mesial and middle coronal pulp. CD11c mRNA in the EG at day 5 was significantly higher than that of the CG and tended to be higher than that of the CG during the observation period. Oct3/4 mRNA expression in the EG was significantly higher than that of the CG at day 7.Conclusions: The current experimental model demonstrated the promotion of the survival of DPSCs and their differentiation into odontoblast-like cells (OBLCs). Thus, the use of this model is expected to clarify the crosstalk mechanism between immune cells, including macrophages and dendritic cells, and DPSCs with regards to pulpal healing after tooth replantation. It also provides insight into the differentiation process of DPSCs into OBLCs.(c) 2023, The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Automated summary

Perforation of the pulp chamber floor promotes pulpal healing and enhances the survival and differentiation of dental pulp stem cells. This study provides insights into the crosstalk mechanism between immune cells and DPSCs, and the differentiation process of DPSCs into odontoblast-like cells.