State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Arch Oral Biol. 2020 Jul;115:104736. doi: 10.1016/j.archoralbio.2020.104736. Epub 2020 Apr 28.
This study aimed to explore the effect of Low-intensity pulsed ultrasound (LIPUS) on implant osseointegration and elucidate the role of α-calcitonin gene-related peptide (αCGRP) in this process.
In vivo, αCGRP (Wild-type model) mice and αCGRP (Knock-out model) mice with implants immediately placed in the maxillary first molars extraction sockets were treated with LIPUS. We detected details of peri-implant bone tissues by micro-CT, real-time PCR and histological analysis. In vitro, αCGRP and αCGRP dorsal root ganglia (DRG) neurons were cultured and exposed to LIPUS. Then conditioned media from these neurons were collected and added to osteoblasts to analyze cell differentiation, mineralization and proliferation by real-time PCR, alkaline phosphatase (ALP) and cell counting kit-8 (CCK-8) assay. Besides, ELISA was performed to determine the effect of LIPUS on the αCGRP secretion in neurons.
In vivo tests revealed that αCGRP mice displayed worse osseointegration when compared to αCGRP mice. LIPUS could enhance implant osseointegration in αCGRP+/+ mice but had little effect on αCGRP mice. Meanwhile, αCGRP was elevated during the osseointegration with LIPUS treatment. In vitro, LIPUS promoted αCGRP secretion in DRG neurons, thereby enhanced osteogenic differentiation and mineralization of osteoblasts. Also we proved that the effects of LIPUS was duty cycle-related and LIPUS of 80% duty cycle had the strongest impacts.
Our findings demonstrated that LIPUS could enhance osseointegration of dental implant by inducing local neuronal production of αCGRP, providing a new idea to promote peri-implant osseointegration and bone regeneration.
本研究旨在探讨低强度脉冲超声（LIPUS）对种植体骨整合的影响，并阐明α-降钙素基因相关肽（αCGRP）在这一过程中的作用。
体内实验中，将αCGRP（野生型模型）和αCGRP（敲除型模型）小鼠的种植体立即植入上颌第一磨牙拔牙窝中，然后用 LIPUS 进行处理。我们通过微 CT、实时 PCR 和组织学分析检测了种植体周围骨组织的细节。体外实验中，培养αCGRP 和αCGRP 背根神经节（DRG）神经元，并对其施加 LIPUS。然后收集这些神经元的条件培养基，并将其添加到成骨细胞中，通过实时 PCR、碱性磷酸酶（ALP）和细胞计数试剂盒-8（CCK-8）测定细胞分化、矿化和增殖情况。此外，还通过 ELISA 测定 LIPUS 对神经元中 αCGRP 分泌的影响。
体内实验表明，与αCGRP 小鼠相比，αCGRP 小鼠的骨整合情况更差。LIPUS 可以增强αCGRP+/+小鼠种植体的骨整合，但对αCGRP 小鼠几乎没有影响。同时，LIPUS 治疗过程中αCGRP 水平升高。体外实验中，LIPUS 促进了 DRG 神经元中 αCGRP 的分泌，从而增强了成骨细胞的成骨分化和矿化。我们还证明了 LIPUS 的作用与占空比有关，80%占空比的 LIPUS 影响最强。
我们的研究结果表明，LIPUS 通过诱导局部神经元产生αCGRP 可以增强种植体的骨整合，为促进种植体周围骨整合和骨再生提供了新的思路。
