低强度脉冲电磁场通过Ca2+/Integrin/FAK通路促进钛种植体表面成骨细胞黏附和增殖的分子机制研究

The implant osseointegration is a complex and slow process. Implant failure still occurs owing to insufficient osseointegration. It is well accepted that early cell adhesion and proliferation on the surface of implant is a prerequisite for obtaining good osseointegration. As one of the main physical method for accelerating osseointegration, low intensity pulsed electromagnetic fields (PEMF) is currently widely used in clinic because of its safety and non-invasive characteristics, but its mechanism needs to be elucidated. We have found in our previous study that PEMF could significantly improve osteoblast adhesion, proliferation and increase cell pseudopodia on the titanium implant surface. Further study showed that PEMF increased the intracellular calcium concentration and the expression of Integrin and as well as the activity phosphorylation of FAK, suggesting that PEMF may improve the osseointegration by regulating osteoblast adhesion and proliferation on the titanium implant surface through the modulation of Ca2+/Integrin/FAK signaling pathway. Based on the previous study, we will systematically use molecular biology methods and construct the animal model , so as to clarify the effect and its underlying molecular mechanism of the PEMF effect on the osteoblast adhesion and proliferation on implant surface, and provide evidence for the wide application of PEMF in the field of oral implantology.

种植体/骨结合过程复杂而缓慢，由于骨结合不足而导致种植失败仍时有发生。研究证实，种植体表面早期细胞黏附和增殖是获得良好骨结合的前提。低强度脉冲电磁场（PEMF）是目前用于加速骨结合的主要物理疗法之一，因其安全、无创的特点已广泛应用于临床并取得了较好疗效，然而其作用机制至今尚未明确。我们前期发现PEMF可显著提高钛种植体表面成骨细胞黏附、伪足数量及增殖水平，进一步研究发现PEMF上调了细胞内钙离子浓度，同时Integrin表达及细胞内外信号转导中枢FAK的磷酸化水平升高，提示PEMF可能通过Ca2+/Integrin/FAK信号通路参与了钛种植体表面成骨细胞的早期黏附和增殖过程，进而促进骨结合。本课题拟在前期基础上，采用细胞和相关分子生物学方法进行系统研究，并构建动物模型加以验证，从而阐明PEMF促进钛种植体表面成骨细胞黏附、增殖的具体分子机制，为PEMF在口腔种植领域的广泛应用奠定基础。

种植体/骨结合过程复杂而缓慢，常导致种植失败。为提高种植体周围骨结合能力，本课题拟通过材料表面改性并加载低强度脉冲电磁场（PEMF）刺激以达到加速种植体骨结合能力的目的。首先，课题组成功构建了阳极氧化组（Nano）钛种植体表面形貌，有效拓展了种植体表面积。通过加载PEMF后检测发现，PEMF可显著提高Nano表面成骨细胞黏附、伪足数量及增殖水平，进一步体外研究发现PEMF上调了成骨细胞内钙离子浓度，同时检测发现，Integrinβ1表达、FAK的磷酸化水平以及其下游关键靶点Rac和Ras表达显著升高，而下调Integrinβ1表达后，成骨细胞黏附数量和增殖显著下降，FAK磷酸化水平降低。此外，动物体内实验也证实PEMF通过促进种植体骨小梁形成并降低周围炎症反应来加速骨结合。该研究初步阐述了PEMF可能通过Ca2+/Integrin/FAK信号通路参与了Nano表面成骨细胞的早期黏附和增殖过程，为PEMF在口腔种植领域的广泛应用奠定基础。受国家自然科学基金资助，申请者以第一作者和通讯作者发表SCI论文3篇，核心期刊1篇，3次在口腔专业学术会议上作专题报告，培养硕士研究生2名。