State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontic and Pediatric dentistry, West China Hospital of Stomatology, Sichuan University, China.
Discipline of Orthodontics, Department of Oral Sciences, Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand.
Arch Oral Biol. 2019 Mar;99:161-168. doi: 10.1016/j.archoralbio.2019.01.014. Epub 2019 Jan 25.
The aim of this study was to investigate the effects of continuous parathyroid hormone (cPTH) and intermittent parathyroid hormone (iPTH) on bone formation and bone resorption in midpalatal suture during maxillary expansion.
Forty-eight male SD rats were randomly divided into four groups (n = 12 each), including the control, the expansion (E), the E + cPTH, and the E + iPTH. A thermosensitive controlled-release hydrogel was synthesized for cPTH administration. All animals were sacrificed after seven days. Microcomputed tomography, histochemical staining and real-time PCR were used to investigate the bone remodeling of midpalatal suture. Serum chemistry was adopted to evaluate the systemic condition of experimental animals.
The suture width was increased by the expansion, and further elevated by cPTH and iPTH administration. Both regimes improved bone volume fraction and trabecular thickness of suture bone region. Moreover, both cPTH and iPTH decreased SOST expression and enhanced the expression of β-catenin and Col-I. cPTH increased RANKL expression, inhibited OPG expression, and resulted in an increment of osteoclasts, while iPTH had no influence on osteoclastogenesis. The serum calcium concentration was enhanced by PTH administration.
Both cPTH and iPTH promote midpalatal suture expansion by enhancing bone formation, probably via SOST downregulation and the resulting β-catenin activation. Our results demonstrated that PTH administration may have potential to be an adjunctive approach for maxillary expansion treatment.
本研究旨在探讨持续甲状旁腺激素（cPTH）和间歇甲状旁腺激素（iPTH）对上颌骨扩弓过程中鼻中隔缝骨形成和骨吸收的影响。
48 只雄性 SD 大鼠随机分为 4 组（每组 n = 12），包括对照组、扩弓组（E 组）、扩弓加 cPTH 组（E + cPTH 组）和扩弓加 iPTH 组（E + iPTH 组）。合成了一种热敏控释水凝胶用于 cPTH 给药。所有动物在 7 天后处死。采用 microCT、组织化学染色和实时 PCR 检测鼻中隔缝的骨重建情况。采用血清化学方法评价实验动物的全身状况。
扩弓可增加鼻中隔缝宽度，cPTH 和 iPTH 给药可进一步增加其宽度。两种治疗方案均改善了缝骨区域的骨体积分数和小梁厚度。此外，cPTH 和 iPTH 均降低了 SOST 的表达，增强了β-catenin 和 Col-I 的表达。cPTH 增加了 RANKL 的表达，抑制了 OPG 的表达，导致破骨细胞增多，而 iPTH 对破骨细胞生成没有影响。PTH 给药可提高血清钙浓度。
cPTH 和 iPTH 通过增强骨形成促进鼻中隔缝扩张，可能通过下调 SOST 和激活β-catenin 实现。我们的结果表明，PTH 给药可能成为上颌骨扩弓治疗的一种辅助方法。
