title: Inhibition of osteogenesis surrounding the titanium implant by CGRP deficiency.
abstract: Previous studies have suggested one of the neurotransmitters, calcitonin gene-related peptide (CGRP), modulates local regulation of bone metabolism; however, the regulating signaling pathway is still being explored. The objective of this study was to determine whether CGRP deficiency affects the osteogenesis surrounding titanium implants in vivo. Titanium screws were implanted in 72 adult rats, which were divided into three groups randomly: Sham, inferior alveolar neurectomy (IAN), and IAN+CGRP. Saline solution containing CGRP (concentration: 100 nmol/L) was injected into the area surrounding the implants in the IAN+CGRP group every day post operation. According to histological observations and Micro-CT, osteogenesis surrounding the implant was suppressed in the IAN group compared to that in the Sham and IAN+CGRP groups; the highest degree of osteogenesis was observed in the Sham group. This effect was also proved via the gene expressions of osteocalcin and runt-related transcription factor 2 surrounding the implant by real-time (RT) PCR analysis. In addition, through immunofluorescence staining and RT-PCR analysis, levels of CGRP and β-catenin were also reduced in the IAN group, while the highest expression was observed in the Sham group (p < 0.05). Our results collectively suggest that the titanium implant bone model established by IAN exhibited CGRP deficiency and reduced osteogenesis surrounding the implant. Additionally, the expression analyses suggest that the canonical Wnt signaling pathway could be involved in this process of bone metabolism in vivo.
authors.affiliation: a State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology , Sichuan University , Chengdu , China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Liu
authors.affiliation: b Guangdong Provincial Key Laboratory of Oral Diseases , Sun Yat-Sen University , Guangzhou , China.
authors.forename: Guangsen
authors.initials: G
authors.lastname: Zheng
authors.affiliation: a State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology , Sichuan University , Chengdu , China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: b Guangdong Provincial Key Laboratory of Oral Diseases , Sun Yat-Sen University , Guangzhou , China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Wang
authors.affiliation: a State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology , Sichuan University , Chengdu , China.
authors.forename: Yiyao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: a State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology , Sichuan University , Chengdu , China.
authors.forename: Qianming
authors.initials: Q
authors.lastname: Chen
authors.affiliation: a State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology , Sichuan University , Chengdu , China.
authors.forename: En
authors.initials: E
authors.lastname: Luo
mesh_terms: D000818:Animals; D001863:Bone Screws / Q000009:adverse effects*; D000069343:Bone-Implant Interface / Q000473:pathology*; D015740:Calcitonin Gene-Related Peptide / Q000172:deficiency*; D005260:Female; D010012:Osteogenesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014025:Titanium / Q000009:adverse effects*
chemical_list: D014025:Titanium; D015740:Calcitonin Gene-Related Peptide
keywords: CGRP; Canonical Wnt signaling pathway; implant; osteogenesis; β-catenin