Department of Orthodontics, Nihon University School of Dentistry at Matsudo, Matsudo, Chiba, Japan.
Eur J Orthod. 2011 Aug;33(4):335-43. doi: 10.1093/ejo/cjq068. Epub 2010 Sep 10.
The differentiation and functions of osteoclasts are regulated by receptor activator of nuclear factor-κB (RANK)/receptor activator of nuclear factor-κB ligand (RANKL) system that stimulates osteoclasts formation. Macrophage colony-stimulating factor (M-CSF) is also essential for osteoclastogenesis. A recent immunocytochemical study reported that RANKL/RANK and M-CSF/c-fms were localized in the periodontal ligament of rat molars during experimental orthodontic tooth movement. The present study focused on the expressions of RANKL/RANK and M-CSF/c-fms in root resorption area during experimental tooth movement in rats. Forty 6-week-old male Wistar rats were subjected to an orthodontic force of 10 or 50 g with a closed coil spring (wire size: 0.005 inch, diameter: 1/12 inch) ligated to the maxillary first molar cleat by a 0.008 inch stainless steel ligature wire to induce a mesial tipping movement of the upper first molars. Experimental tooth movement was undertaken for 10 days. Each sample was sliced into 6 μm continuous sections in a horizontal direction and prepared for haematoxylin and eosin (H and E) and immunohistochemistry staining for tartrate-resistant acid phosphatase (TRAP), RANK, RANKL M-CSF, and c-fms in root resorption area. Statistical analysis was carried out using a Mann-Whitney U-test with a significance level of P<0.01. On days 7 and 10, immunoreactivity for RANKL/RANK and M-CSF/c-fms was detected in odontoclasts with an orthodontic force of 50 g, but not 10 g. Therefore, RANKL/RANK and M-CSF/c-fms systems may be involved in the process of root resorption by heavy orthodontic force.
破骨细胞的分化和功能受核因子-κB 受体激活剂（RANK）/核因子-κB 受体激活剂配体（RANKL）系统的调节，该系统刺激破骨细胞的形成。巨噬细胞集落刺激因子（M-CSF）对于破骨细胞的形成也是必不可少的。最近的一项免疫细胞化学研究报告称，在实验性正畸牙齿移动期间，RANKL/RANK 和 M-CSF/c-fms 定位于大鼠磨牙的牙周韧带中。本研究重点研究了在大鼠实验性牙齿移动过程中，RANKL/RANK 和 M-CSF/c-fms 在根吸收区域的表达。40 只 6 周龄雄性 Wistar 大鼠用闭合线圈弹簧（线径：0.005 英寸，直径：1/12 英寸）施加 10 或 50g 的正畸力，通过 0.008 英寸不锈钢结扎丝结扎在上颌第一磨牙的 cleat 上，以诱导上颌第一磨牙的近中倾斜运动。进行了 10 天的实验性牙齿移动。每个样本在水平方向上切成 6μm 连续切片，并准备用于根吸收区的苏木精和伊红（H 和 E）以及抗酒石酸酸性磷酸酶（TRAP）、RANK、RANKL M-CSF 和 c-fms 的免疫组织化学染色。使用 Mann-Whitney U 检验进行统计分析，显著性水平为 P<0.01。在第 7 天和第 10 天，在施加 50g 正畸力的情况下，破骨细胞中检测到 RANKL/RANK 和 M-CSF/c-fms 的免疫反应性，但施加 10g 正畸力时则没有。因此，RANKL/RANK 和 M-CSF/c-fms 系统可能参与了重正畸力导致的牙根吸收过程。
