Ploysongsang Kwanrat, Kobayashi Yukiho, Lu Yeming, Niki Yuki, Chavanavesh Janeta, Moriyama Keiji
Department of Maxillofacial Orthognathics, Division of Maxillofacial and Neck Reconstruction, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
Department of Orthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand.
Sci Rep. 2025 Jul 1;15(1):21468. doi: 10.1038/s41598-025-07949-9.
During orthodontic tooth movement (OTM), local hypoxia on the compression side stimulates cellular remodelling of periodontal tissues. We investigated the effects of systemic, sustained hypoxia on OTM in vivo. OTM was performed on the right maxillary first molar (M1) of 8-week-old male Sprague-Dawley rats using a 10-gf nickel-titanium closed-coil spring for 4 weeks under control (21% O, n = 9) or hypoxic (10% O, n = 9) conditions. Micro-computed tomography was used to measure OTM distances, alveolar bone morphometric parameters, and M1 buccal alveolar bone levels. Osteoclast differentiation and periodontal ligament (PDL) cell proliferation were determined using tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemistry, respectively. Runt-related transcription factor 2 (RUNX2) and vascular endothelial growth factor (VEGF) expression in M1 periodontal tissues were analysed using immunofluorescence. The hypoxia-OTM group showed significantly accelerated tooth movement, significantly decreased M1 buccal alveolar bone levels, significantly greater numbers of TRAP-positive cells on the compression side, and significantly reduced Ki67-positive ratios in PDL tissues. The VEGF and RUNX2 fluorescence intensities on the tension side were higher in the control-OTM than in the hypoxia-OTM group. Our results demonstrate that systemic, sustained hypoxia affects OTM by altering osteoclast and osteoblast differentiation in vivo, resulting in reduced alveolar bone levels after OTM.
在正畸牙齿移动（OTM）过程中，压缩侧的局部缺氧会刺激牙周组织的细胞重塑。我们研究了全身持续性缺氧对体内OTM的影响。使用10克力的镍钛闭合螺旋弹簧对8周龄雄性Sprague-Dawley大鼠的右上颌第一磨牙（M1）进行OTM操作，在对照（21%氧气，n = 9）或缺氧（10%氧气，n = 9）条件下持续4周。采用微型计算机断层扫描测量OTM距离、牙槽骨形态计量学参数以及M1颊侧牙槽骨水平。分别使用抗酒石酸酸性磷酸酶（TRAP）染色和免疫组织化学法测定破骨细胞分化和牙周膜（PDL）细胞增殖情况。采用免疫荧光法分析M1牙周组织中与 runt 相关的转录因子2（RUNX2）和血管内皮生长因子（VEGF）的表达。缺氧-OTM组显示牙齿移动明显加速，M1颊侧牙槽骨水平显著降低，压缩侧TRAP阳性细胞数量显著增多，PDL组织中Ki67阳性率显著降低。对照-OTM组张力侧的VEGF和RUNX2荧光强度高于缺氧-OTM组。我们的结果表明，全身持续性缺氧通过改变体内破骨细胞和成骨细胞的分化来影响OTM，导致OTM后牙槽骨水平降低。
