Ueda Masae, Goto Tetsuya, Kuroishi Kayoko N, Gunjigake Kaori K, Ikeda Erina, Kataoka Shinji, Nakatomi Mitsushiro, Toyono Takashi, Seta Yuji, Kawamoto Tatsuo
Division of Orofacial Functions and Orthodontics, Kyushu Dental University, 2-6-1, Manazuru, Kokurakita-ku, Kitakyushu 803-8580, Japan.
Department of Oral Anatomy and Cell Biology, Kagoshima University, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan.
Arch Oral Biol. 2016 Feb;62:86-92. doi: 10.1016/j.archoralbio.2015.11.010. Epub 2015 Nov 22.
During orthodontic tooth movement, bone resorption and inhibition of bone formation occur on the compressed side, thereby preventing ankylosis. Periodontal ligament (PDL) cells control bone metabolism and inhibition of bone formation on the compressed side by secreting bone-formation inhibitory factors such as asporin (ASPN) or sclerostin (encoded by SOST). The aim of this study was to identify the inhibitory factors of bone formation in PDL cells.
In vitro, the changes in expression of ASPN and SOST and subsequent protein release in human PDL (hPDL) cells were assessed by semi-quantitative polymerase chain reaction (PCR), real-time PCR, and immunofluorescence in hPDL cells subjected to centrifugal force using a centrifuge (45, 90, 135, and 160 × g). In vivo, we applied a compressive force using the Waldo method in rats, and examined the distribution of ASPN or sclerostin by immunohistochemistry.
In vitro, hPDL cells subjected to 90 × g for 24h demonstrated upregulated ASPN and downregulated SOST expressions, which were confirmed by immunofluorescent staining. In addition, the formation of mineralized tissue by human osteoblasts was significantly inhibited by the addition of medium from hPDL cells cultured during compressive force as well as the addition of equivalent amounts of ASPN peptide. In vivo, asporin-positive immunoreactive PDL cells and osteoclasts were found on the compressed side, whereas few sclerostin-positive PDL cells were observed.
PDL cells subjected to an optimal compressive force induce the expression and release of ASPN, which inhibits bone formation during orthodontic tooth movement on the compressed side.
在正畸牙齿移动过程中，压缩侧会发生骨吸收以及骨形成的抑制，从而防止牙齿粘连。牙周膜（PDL）细胞通过分泌骨形成抑制因子如阿朴脂蛋白（ASPN）或硬化蛋白（由SOST编码）来控制压缩侧的骨代谢和骨形成抑制。本研究的目的是确定PDL细胞中骨形成的抑制因子。
在体外，通过半定量聚合酶链反应（PCR）、实时PCR以及对使用离心机施加离心力（45、90、135和160×g）的人牙周膜（hPDL）细胞进行免疫荧光，评估hPDL细胞中ASPN和SOST表达的变化以及随后的蛋白质释放。在体内，我们采用瓦尔斗方法对大鼠施加压缩力，并通过免疫组织化学检查ASPN或硬化蛋白的分布。
在体外，施加90×g离心力24小时的hPDL细胞显示ASPN表达上调和SOST表达下调，这通过免疫荧光染色得到证实。此外，添加在压缩力作用下培养的hPDL细胞的培养基以及添加等量的ASPN肽，可显著抑制人成骨细胞矿化组织的形成。在体内，在压缩侧发现了阿朴脂蛋白阳性免疫反应性PDL细胞和破骨细胞，而观察到的硬化蛋白阳性PDL细胞很少。
受到最佳压缩力作用的PDL细胞诱导ASPN的表达和释放，ASPN在正畸牙齿移动过程中抑制压缩侧的骨形成。
