Whether external root resorption is associated with hypoxia in the periodontal ligaments of teeth with severe periodontitis remains unclear. Hypoxia inducible factor-1α (HIF-1α) expression and external resorption sites in the periodontal ligaments of these teeth were observed to elaborate upon the relationship between hypoxia and external root resorption in severe periodontitis. Histological analysis was performed to observe external root resorption. The expressions of HIF-1α and Nuclear factor-activated T cells c1 (NFATc1) in the periodontal ligaments were detected by immunofluorescence, western blotting and real-time PCR. Bone marrow macrophages (BMMs) were stimulated by Porphyromonas gingivalis lipopolysaccharide (Pg.LPS) and cultured under hypoxia in vitro. High levels of HIF-1α and NFATc1 were detected in severe periodontitis. HIF-1α positive-cells were observed in the external resorption sites. Hypoxia promoted Pg.LPS-stimulated osteoclastogenesis of BMMs and bone resorption by the NFATc1 pathway. Increased HIF-1α in severe periodontitis are associated with external root resorption by the NFATc1 pathway.

尚不清楚外牙根吸收与重度牙周炎的牙齿牙周膜缺氧是否相关。观察到缺氧诱导因子-1α（HIF-1α）的表达和这些牙齿的牙周膜中的外部吸收位点阐明了严重牙周炎中缺氧与外部牙根吸收之间的关系。进行组织学分析以观察外部根吸收。通过免疫荧光，western blotting和实时荧光定量PCR检测HIF-1α和核因子激活的T细胞c1（NFATc1）在牙周膜中的表达。牙龈卟啉单胞菌脂多糖（Pg.LPS）刺激骨髓巨噬细胞（BMM），并在缺氧条件下进行体外培养。在严重的牙周炎中检测到高水平的HIF-1α和NFATc1。在外部吸收位点观察到HIF-1α阳性细胞。低氧促进了Pg.LPS刺激的BMM破骨细胞生成和NFATc1途径的骨吸收。严重牙周炎中HIF-1α的增加与NFATc1途径引起的外部根吸收有关。