Time-Course Study of Genetic Changes in Periodontal Ligament Regeneration in Tooth Transplantation. Mus musculus

This study aimed to comprehensively analyze gene expression in the periodontal ligament (PDL) following reimplantation to elucidate the genes and pathways involved in healing and regeneration after treatment. Using a mouse model for intentional tooth replantation, mRNA was extracted from the PDL at various intervals post-replantation for comparative transcriptome analysis via RNA sequencing (RNA-seq). The analysis covered intervals from 3 days to 8 weeks post-replantation. Results showed significant changes in gene expression patterns, especially on day 28. Hierarchical clustering and principal component analysis further validated these findings. Gene ontology (GO) enrichment analysis revealed an upregulation of olfactory and G protein-coupled receptor signaling pathways at day 28. qRT-PCR validation confirmed the transient expression of olfactory receptor genes, and immunochemical staining further localized this expression to the PDL and adjacent tissue. Additionally, a scratch assay using human PDL fibroblasts indicated a potential role for the olfactory receptor gene in wound healing, suggesting that a transient increase in olfactory receptor gene expression might aid optimal PDL healing. On the other hand, by 14 days post-replantation, there was an increase in inflammatory pathways and a decrease in genes linked to keratinization and epithelial barrier function. These results underscore the importance of the 28-day post-transplant phase as a potential "tipping point" in PDL healing and regeneration. In conclusion, this research provides insights into the gene expression patterns during the PDL's healing and regeneration processes, highlighting the potential role of olfactory receptor genes.

本研究旨在全面分析牙齿再植后牙周膜（periodontal ligament, PDL）的基因表达情况，以阐明牙齿再植术后愈合与再生过程中涉及的基因及信号通路。本研究采用计划性牙齿再植术构建小鼠模型，于再植后不同时间点从牙周膜中提取信使RNA（messenger RNA, mRNA），借助RNA测序（RNA-seq）开展比较转录组学分析，分析覆盖了再植后3天至8周的多个时间节点。结果显示，牙周膜的基因表达谱发生了显著变化，尤其在再植后第28天最为明显。层级聚类分析与主成分分析进一步验证了上述结果。基因本体（Gene Ontology, GO）富集分析显示，第28天时嗅觉信号通路与G蛋白偶联受体（G protein-coupled receptor）信号通路出现显著上调。反转录实时定量PCR（quantitative real-time reverse transcription PCR, qRT-PCR）验证证实，嗅觉受体（olfactory receptor）基因呈瞬时表达模式；免疫化学染色（immunochemical staining）进一步将该表达定位至牙周膜及其邻近组织。此外，利用人牙周膜成纤维细胞开展的划痕实验（scratch assay）显示，嗅觉受体基因可能参与伤口愈合过程，提示嗅觉受体基因的瞬时上调或许有助于牙周膜实现最佳愈合效果。另一方面，再植后14天时，炎症相关通路出现上调，而与角质化及上皮屏障功能相关的基因表达则出现下调。上述结果凸显了再植后28天这一阶段作为牙周膜愈合与再生过程潜在"tipping point"的重要性。综上，本研究阐明了牙周膜愈合与再生过程中的基因表达谱特征，凸显了嗅觉受体基因的潜在调控作用。