Sympathetic nervous system contributes to orthodontic tooth movement by central neural regulation from hypothalamus
Haifeng Cao1, Bing Fang1, Xudong Wang1 and Yanheng Zhou2
1Department of Orthodontics, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology and Shanghai Rearch Institute of Stomatology, Shanghai and 2Department of Orthodontics, Center for Craniofacial Stem Cell Research and Regeneration, Peking University School and Hospital of Stomatology, Beijing, China
Offprint requests to: Bing Fang or Xudong Wang, Department of Orthodontics, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology and Shanghai Rearch Institute of Stomatology, 639 Zhi Zao Ju Road, Shanghai 200011, China. e-mail: braces_dr@hotmail.com or xudongwang70@hotmail.com or Yanheng Zhou, Department of Orthodontics,Center for Craniofacial Stem Cell Research and Regeneration, Peking University School and Hospital of Stomatology, 12 South Zhong Guan Cun Road, Beijing 100086, China. e-mail: yanhengzhou@gmail.com
Summary. Orthodontic tooth movement (OTM) is a specific treatment of malocclusion, whose regulation mechanism is still not clear. This study aimed to reveal the relationship between the sympathetic nervous system (SNS) and OTM through the construction of an OTM rat model through the utilization of orthodontic nickeltitanium coiled springs. The results indicated that the stimulation of SNS by dopamine significantly promote the OTM process represented by the much larger distance between the first and second molar compared with mere exertion of orthodontic force. Superior cervical ganglionectomy (SCGx) can alleviate this promotion effect, further proving the role of SNS in the process of OTM. Subsequently, the ability of orthodontic force to stimulate the center of the SNS was visualized by the tyrosin hydroxylase (TH) staining of neurons in ventromedial hypothalamic nucleus (VMH) and arcuate nucleus (ARC) of the hypothalamus, as well as the up-regulated expression of norepinephrine in local alveolar bone. Moreover, we also elucidated that the stimulation of SNS can promote osteoclast differentiation in periodontal ligament cells (PDLCs) and bone marrow-derived cells (BMCs) through regulation of receptor activator of nuclear factor-?B ligand (RANKL)/osteoprotegerin (OPG) system, thus promoting the OTM process. In conclusion, this study provided the first evidence for the involvement of the hypothalamus in the promotion effect of SNS on OTM. This work could provide a novel theoretical and experimental basis for further understanding of the molecular mechanism of OTM. Histol Histopathol 35, 1493-1502 (2020)
Key words: Orthodontic tooth movement, Sympathetic nervous system, Dopamine, Periodontal ligament cells, Hypothalamus
DOI: 10.14670/HH-18-280