Effect of the IL-34 in mononuclear-macrophage of the alveolar socket healing in aging mice

PAN Wen; SHAN Zhao-chen

doi:10.19749/j.cn.cjgd.1672-2973.2025.04.001

Abstract：Objective To investigate the impact of bone immunity on alveolar bone healing in aging mice and to establish a theoretical foundation for the development of novel anti-aging immunotherapies or intervention strategies.Methods Eight-week-old and 18-month-old C57BL/6J mice were utilized as representatives of the young group and the senescent group,respectively,with 15 mice in each group.The first upper molar was extracted to establish an alveolar bone healing model following tooth extraction.One week post-extraction,transcriptome sequencing was performed to analyze gene expression in mononuclear-macrophages,flow cytometry was used to quantify subgroup proportions,and enzyme-linked immunosorbent assay(ELISA)and Western blotting were employed to validate the expression of relevant genes and target proteins.Three weeks after modeling,micro-computed tomography(Micro-CT)was utilized to evaluate alveolar bone healing.Results Micro-CT analysis revealed that alveolar bone healing in the upper jaw of the young group was superior to that of the aging group,with significantly higher bone density and bone volume in the young group compared to the aging group(P＜0.05).Flow cytometry demonstrated that the number of mononuclear-macrophages in the alveolar bone of the aging group was markedly higher than in the young group(P＜0.05).Compared to the young group as the control,there were 103 differentially expressed genes identified,including 62 upregulated genes and 41 downregulated genes.ELISA results indicated that the level of IL-34 in the alveolar bone tissue of the aging group was significantly higher than in the young group(P＜0.05).Polymerase chain reaction(PCR)detection confirmed that the expression level of IL-34 in mononuclear-macrophages of the aging group was significantly elevated compared to the young group(P＜0.05).The addition of IL-34 notably promoted cell proliferation and enhanced the phosphorylation of PI3K protein,thereby activating the PI3K/Akt signaling pathway.Conclusion IL-34 enhances the proliferation of mononuclear-macrophages during alveolar bone healing in aging mice by activating the PI3K/Akt signaling pathway.