正畸治疗过程中，牙齿主要通过机械力转化为生物信号后导致的牙周改建来实现移动。而牙周改建的细胞分子机制尚需深入探讨和研究。本研究拟利用四点弯曲加力装置对人牙周膜成纤维细胞、人成骨细胞加载压应力，模拟正畸牙移动过程中的压力侧的加力环境。采用RT-PCR，Western Blot等方法观察Eph-ephrin信号分子及MAPK下游信号分子在基因水平及蛋白水平表达的变化特点，同时利用Eph-ephrin信号特异性激活剂及MAPK信号通路特异性阻断剂探讨Eph-ephrin信号通路与MAPK信号通路的交叉联系，预测Eph-ephrin信号通路在牙周改建方面的其他潜在信号通路。进一步加深对Eph-ephrin双向转导信号在正畸牙移动牙周改建机制的理解，从而为改善治疗策略或更为精确合理的控制牙齿移动提供理论依据。

For orthodontic treatment, the teeth move though the periodontial remodeling by transferring the mechanical forces into biological signaling. The transduction mechanisms from mechanical loading to the periodontial remodeling are not clearly understood. This study intends to observe the Eph-eprhin bidirectional signal transduction and the phosphorylation of extracellular signal-regulated kinases 1/2.of hPDLFs and OB in genes expression level by real-time PCR and protein expression level by Western Blot by using the four-point bending apparatus. At the same time, the cross-relationship of the Eph-ephrin signal transduciton and MAPK signal transduction could be observed by stimualting the Eph forward signaling, the ephrin backword signaling and inhibiting the MAPK signalling (specific MEK1/2 inhibitor) in hPDLFs and OB. Some other potential signal transduction could be forecasted to involve in the Eph-ephrin siganl transduction. Our objective is to provide a theoretical basis for improving therapeutic strategies for orthodontic tooth movement.