Zhu Yafen, Gu Liqun, Wang Jian, Han Jie, Gou Junzhuo, Wu Zhifang
Department of Pediatric Dentistry, Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province, Hangzhou, 310000, China.
BMC Oral Health. 2024 Dec 4;24(1):1474. doi: 10.1186/s12903-024-05269-4.
Tooth movement induced orofacial pain is the most cited negative effect during orthodontic treatment, while treatment options without side effects are limited. The differential expression of pain-related genes due to DNA methylation and demethylation is instrumental in pain. The purpose of the study was to evaluate the DNA methylation profiling of CpG islands (CGI) and CGI shores in promoter regions in trigeminal ganglions (TG) of tooth movement induced orofacial pain rats, thus to further insight the DNA methylation regulation in orofacial pain.
An orofacial pain rat model was constructed by ligating coil springs between the incisor and first maxillary molar with 40 g of force. The Rat Grimace Score (RGS) was used for pain evaluation. The genome methylation status was analyzed by the reduced representation bisulfite sequencing (RRBS) technique. Gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analyses were conducted in the differentially methylated regions (DMRs). Moreover, a protein-protein interaction (PPI) network was established to detect annotated genes associated with pain.
RGS was significantly higher in orofacial pain rats than in sham rats. RRBS showed widespread methylation changes in CGI and CGI shores in TG promoter regions. Both 902 hypermethylated DMRs and 862 hypomethylated DMRs were found in the CGIs of promoter regions. KEGG analysis revealed that annotated genes are participated in endocrine, nervous, immune, and sensory systems. Moreover, the "Calcium signaling pathway", "Wnt signaling pathway" and "Neuroactive ligand-receptor interaction" were significantly enriched pathways. Furthermore, PPI network showed several genes (Ctnnb1, Dlg4, Creb1, Camk2g, Bmp2, etc.) with different methylation statuses were reported to be associated with pain.
This study demonstrated methylation changes were existed in CGI and CGI shores in TG promoter regions when pain occurs, thus providing a basis for further study on the mechanism of DNA methylation in orofacial pain.
正畸治疗期间，牙齿移动引起的口面部疼痛是最常被提及的负面影响，而无副作用的治疗选择有限。由于DNA甲基化和去甲基化导致的疼痛相关基因的差异表达在疼痛中起作用。本研究的目的是评估牙齿移动诱导的口面部疼痛大鼠三叉神经节（TG）启动子区域中CpG岛（CGI）和CGI边缘的DNA甲基化谱，从而进一步深入了解口面部疼痛中的DNA甲基化调控。
通过以40 g的力在门牙和上颌第一磨牙之间结扎螺旋弹簧构建口面部疼痛大鼠模型。采用大鼠面部表情评分（RGS）进行疼痛评估。通过简化代表性亚硫酸氢盐测序（RRBS）技术分析基因组甲基化状态。在差异甲基化区域（DMR）中进行基因本体（GO）和京都基因与基因组百科全书（KEGG）分析。此外，建立蛋白质-蛋白质相互作用（PPI）网络以检测与疼痛相关的注释基因。
口面部疼痛大鼠的RGS显著高于假手术大鼠。RRBS显示TG启动子区域的CGI和CGI边缘存在广泛的甲基化变化。在启动子区域的CGI中发现了902个高甲基化DMR和862个低甲基化DMR。KEGG分析显示注释基因参与内分泌、神经、免疫和感觉系统。此外，“钙信号通路”、“Wnt信号通路”和“神经活性配体-受体相互作用”是显著富集的通路。此外，PPI网络显示几个甲基化状态不同的基因（Ctnnb1、Dlg4、Creb1、Camk2g、Bmp2等）与疼痛相关。
本研究表明疼痛发生时TG启动子区域的CGI和CGI边缘存在甲基化变化，从而为进一步研究口面部疼痛中DNA甲基化的机制提供了依据。
