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Inhibition of osteogenesis surrounding the titanium implant by CGRP deficiency
Yao Liu1, Guangsen Zheng2, Li Liu1
1a State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology , Sichuan University , Chengdu , China.
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.
Insights
Calcitonin gene-related peptide (CGRP) deficiency impairs bone healing around titanium implants. Restoring CGRP levels improved osteogenesis, suggesting CGRP
Area of Science:
- Biomaterials Science
- Neuroscience
- Orthopedics
Background:
- Calcitonin gene-related peptide (CGRP) is implicated in bone metabolism regulation.
- The specific signaling pathways CGRP uses in bone regeneration are not fully understood.
- Osteogenesis around titanium implants is crucial for successful osseointegration.
Purpose of the Study:
- To investigate the effect of CGRP deficiency on osteogenesis surrounding titanium implants in an in vivo model.
- To explore the role of CGRP in the bone healing process following dental implant placement.
Main Methods:
- Titanium screws were implanted in 72 rats, divided into Sham, inferior alveolar neurectomy (IAN), and IAN+CGRP groups.
- CGRP or saline was administered daily to the surgical sites.
- Histological analysis, Micro-CT, RT-PCR, and immunofluorescence staining were used to assess osteogenesis and gene expression.
Main Results:
- CGRP deficiency (IAN group) significantly suppressed osteogenesis around titanium implants compared to Sham and IAN+CGRP groups.
- Gene expression of osteocalcin and runt-related transcription factor 2 was reduced in the IAN group.
- CGRP and β-catenin levels were decreased in the IAN group, indicating CGRP's involvement in Wnt signaling.
Conclusions:
- IAN-induced titanium implant model demonstrates CGRP deficiency and impaired osteogenesis.
- CGRP plays a vital role in promoting osteogenesis around titanium implants.
- The canonical Wnt signaling pathway may mediate CGRP's effects on bone metabolism in vivo.