Altered DNA methylation upon ageing may result in many age‐related diseases such as osteoporosis. However, the changes in DNA methylation that occur in cortical bones, the major osteocytic areas, remain unknown. In our study, we extracted total DNA and RNA from the cortical bones of 6‐month‐old and 24‐month‐old mice and systematically analysed the differentially methylated regions (DMRs), differentially methylated promoters (DMPs) and differentially expressed genes (DEGs) between the mouse groups. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the DMR‐related genes revealed that they were mainly associated with metabolic signalling pathways, including glycolysis, fatty acid and amino acid metabolism. Other genes with DMRs were related to signalling pathways that regulate the growth and development of cells, including the PI3K‐AKT, Ras and Rap1 signalling pathways. The gene expression profiles indicated that the DEGs were mainly involved in metabolic pathways and the PI3K‐AKT signalling pathway, and the profiles were verified through real‐time quantitative PCR ( RT‐qPCR). Due to the pivotal roles of the affected genes in maintaining bone homeostasis, we suspect that these changes may be key factors in age‐related bone loss, either together or individually. Our study may provide a novel perspective for understanding the osteocyte and its relationship with osteoporosis during ageing.

中文翻译：

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老年和幼年小鼠骨细胞区域DNA甲基化和差异基因表达的比较概况。

老化后DNA甲基化的改变可能导致许多与年龄有关的疾病，例如骨质疏松症。然而，在皮质骨（主要的骨质疏松区域）中发生的DNA甲基化变化仍然未知。在我们的研究中，我们从6个月大和24个月大的小鼠的皮质骨骼中提取了总DNA和RNA，并系统分析了差异甲基化区域（DMR），差异甲基化启动子（DMP）和差异表达基因（DEG） ）之间的鼠标。对DMR相关基因的《京都基因与基因组百科全书》（KEGG）通路分析表明，它们主要与代谢信号通路相关，包括糖酵解，脂肪酸和氨基酸代谢。其他具有DMR的基因与调节细胞生长和发育的信号通路有关，包括PI3K-AKT，Ras和Rap1信号通路。基因表达谱表明DEGs主要参与代谢途径和PI3K-AKT信号传导途径，并通过实时定量PCR（RT-qPCR）进行了验证。由于受影响的基因在维持骨稳态方面的关键作用，我们怀疑这些变化可能是与年龄相关的骨丢失的关键因素，无论是一起还是单独出现。我们的研究可能为了解骨细胞及其与衰老过程中骨质疏松的关系提供一个新颖的观点。由于受影响的基因在维持骨稳态中的关键作用，我们怀疑这些变化可能是与年龄相关的骨丢失的关键因素，无论是一起还是单独出现。我们的研究可能为了解骨细胞及其与衰老过程中骨质疏松的关系提供一个新颖的观点。由于受影响的基因在维持骨稳态中的关键作用，我们怀疑这些变化可能是与年龄相关的骨丢失的关键因素，无论是一起还是单独出现。我们的研究可能为了解骨细胞及其与衰老过程中骨质疏松的关系提供一个新颖的观点。