Takayuki Miyazaki1,2, Ryota Kurimoto2, Tomoki Chiba2, Takahide Matsushima2, Ryo Nakamichi3, Hiroki Tsutsumi2, Kaho Takada2,4, Lisa Yagasaki2,5, Tomomi Kato2, Kana Shishido2, Yukiho Kobayashi1, Tsutomu Matsumoto1, Keiji Moriyama6, Hiroshi Asahara7,8. 1. Department of Maxillofacial Orthognathics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8510, Japan. 2. Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45Bunkyo-ku, YushimaTokyo, Japan. 3. Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA. 4. Department of Oral and Maxillofacilal Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan. 5. Department of Periodontology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan. 6. Department of Maxillofacial Orthognathics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8510, Japan. k-moriyama.mort@tmd.ac.jp. 7. Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45Bunkyo-ku, YushimaTokyo, Japan. asahara.syst@tmd.ac.jp. 8. Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA. asahara.syst@tmd.ac.jp.
Abstract
INTRODUCTION: The periodontal ligament (PDL) plays an important role in orthodontic tooth movement; however, the underlying molecular mechanism remains unclear. We have previously reported that the Mohawk homeobox (Mkx), a tendon-specific transcription factor, is expressed in the PDL and regulates its homeostasis. MATERIALS AND METHODS: In the present study, we examined the role of Mkx in orthodontic tooth movement via bone remodeling induced by mechanical stimulation in Mkx-deficient rats, which are widely used as experimental animals for orthodontic force application. Orthodontic tooth movement of the maxillary first molar was performed in 7-week-old male Mkx-deficient rats (n = 4) and wild-type Wistar rats (n = 4) using coil springs for 14 days. Hematoxylin and eosin (H&E) staining and tartrate-resistant acid phosphatase (TRAP) staining were performed to evaluate morphological changes and osteoclasts. Furthermore, changes in the expression of receptor activator nuclear factor-kappa B ligand (RANKL) were demonstrated using immunostaining. RESULTS: The amount of tooth movement was significantly lower in Mkx-deficient rats than in wild-type rats. The number of TRAP-positive cells was suppressed in Mkx-deficient rats on the compression side. CONCLUSION: Orthodontic tooth movement experiments in Mkx-deficient rats suggested that Mkx is involved in osteoclast induction at the alveolar bone surface on the compression side. This study reveals the possibility that Mkx plays a mechanosensory role in orthodontic tooth movement by inducing RANKL expression and osteoclastogenesis.
INTRODUCTION: The periodontal ligament (PDL) plays an important role in orthodontic tooth movement; however, the underlying molecular mechanism remains unclear. We have previously reported that the Mohawk homeobox (Mkx), a tendon-specific transcription factor, is expressed in the PDL and regulates its homeostasis. MATERIALS AND METHODS: In the present study, we examined the role of Mkx in orthodontic tooth movement via bone remodeling induced by mechanical stimulation in Mkx-deficient rats, which are widely used as experimental animals for orthodontic force application. Orthodontic tooth movement of the maxillary first molar was performed in 7-week-old male Mkx-deficient rats (n = 4) and wild-type Wistar rats (n = 4) using coil springs for 14 days. Hematoxylin and eosin (H&E) staining and tartrate-resistant acid phosphatase (TRAP) staining were performed to evaluate morphological changes and osteoclasts. Furthermore, changes in the expression of receptor activator nuclear factor-kappa B ligand (RANKL) were demonstrated using immunostaining. RESULTS: The amount of tooth movement was significantly lower in Mkx-deficient rats than in wild-type rats. The number of TRAP-positive cells was suppressed in Mkx-deficient rats on the compression side. CONCLUSION: Orthodontic tooth movement experiments in Mkx-deficient rats suggested that Mkx is involved in osteoclast induction at the alveolar bone surface on the compression side. This study reveals the possibility that Mkx plays a mechanosensory role in orthodontic tooth movement by inducing RANKL expression and osteoclastogenesis.
Entities:
Keywords:
Mohawk; Orthodontic tooth movement; Osteoclast; PDL; Rat
Authors: Carmen Gonzales; Hitoshi Hotokezaka; Masako Yoshimatsu; Joseph H Yozgatian; M Ali Darendeliler; Noriaki Yoshida Journal: Angle Orthod Date: 2008-05 Impact factor: 2.079
Authors: K Terai; T Takano-Yamamoto; Y Ohba; K Hiura; M Sugimoto; M Sato; H Kawahata; N Inaguma; Y Kitamura; S Nomura Journal: J Bone Miner Res Date: 1999-06 Impact factor: 6.741