title: Periodontal CGRP contributes to orofacial pain following experimental tooth movement in rats.
abstract: Calcitonin-related gene peptide (CGRP) plays an important role in orofacial inflammatory pain. The aim of this study was to determine whether periodontal CGRP contributes to orofacial pain induced by experimental tooth movement in rats. Male Sprague-Dawley rats were used in this study. Closed coil springs were used to deliver forces. Rats were euthanized on 0d, 1d, 3d, 5d, 7d, and 14d following experimental tooth movement. Then, alveolar bones were obtained for immunostaining of periodontal tissues against CGRP. Two hours prior to euthanasia on each day, orofacial pain levels were assessed through rat grimace scale. CGRP and olcegepant (CGRP receptor antagonist) were injected into periodontal tissues to verify the roles of periodontal CGRP in orofacial pain induced by experimental tooth movement. Periodontal CGRP expression levels and orofacial pain levels were elevated on 1d, 3d, 5d, and 7d following experimental tooth movement. The two indices were significantly correlated with each other and fitted into a dose-response model. Periodontal administration of CGRP could elevate periodontal CGRP expressions and exacerbate orofacial pain. Moreover, olcegepant administration could decrease periodontal CGRP expressions and alleviate orofacial pain. Therefore, periodontal CGRP plays an important role in pain transmission and modulation following experimental tooth movement. We suggest that it may participate in a positive feedback aiming to amplify orofacial pain signals.
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Long
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Liao
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Meiya
authors.initials: M
authors.lastname: Gao
authors.affiliation: West China School of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Wenqiang
authors.initials: W
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Jian
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China. Electronic address: wenlilai@scu.edu.cn.
authors.forename: Wenli
authors.initials: W
authors.lastname: Lai
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D005157:Facial Pain / Q000378:metabolism*; D008297:Male; D059225:Nociception / Q000502:physiology*; D010147:Pain Measurement; D051381:Rats; D017207:Rats, Sprague-Dawley; D014086:Tooth Mobility / Q000378:metabolism*
chemical_list: D015740:Calcitonin Gene-Related Peptide
keywords: CGRP; Pain; Periodontal tissue; Tooth movement; Trigeminal ganglion