ERK信号通路参与调控周期性张应变诱导的人牙周膜细胞增殖

目的 探讨周期性张应变对人牙周膜细胞 （human periodontal ligament cell , hPDLCs ) 增殖的影响及其相关机制。方法 应用FX-4000T 细胞应变加载系统，对体外培养的人牙周膜细胞施加周期性张应变，幅度分别为10 % 和20 %，加载时间为6 h和24 h，频率均为0.1 Hz，以未加载的静态细胞作为对照组。Western blot 法检测细胞增殖细胞核抗原（PCNA）和细胞内信号转导分子p-ERK1/2表达的变化。用ERK1/2的特异性抑制剂PD 98059预处理细胞后，在0.1 Hz，10 % 幅度条件下，加载6 h，检测p-ERK1/2的表达水平变化对细胞PCNA表达的影响。 结果 与静态组相比，周期性张应变诱导人牙周膜细胞的PCNA和p-ERK1/2表达增加，10 % 幅度和20 % 幅度相比无显著性差异。同一幅度张应变，加载6 h和24 h对细胞PCNA和p-ERK1/2表达的影响无显著性差异。ERK1/2的抑制剂PD98059不仅可以明显抑制张应变诱导的p-ERK1/2 活化，而且张应变诱导的细胞PCNA表达也被明显抑制。结论 周期性张应变可激活ERK信号通路，促进体外培养人牙周膜细胞的增殖。

Cyclic strain promotes proliferation of human periodontal ligament cell via ERK signaling pathway

Objective To explore the role of extracellular signal-regulated kinase (ERK) signaling pathway on cyclic strain induced proliferation of human periodontal ligament cell (hPDLCs). Methods The cultured hPDLCs in vitro were subjected to cyclic strain by FX-4000T system with 10 % or 20 %-elongation magnitude, 6 or 24 hours-duration respectively, at the same frequency of 0.1 Hz. The expressions of p-ERK1/2 and PCNA in hPDLCs were analyzed by Western blotting. To investigate the effect of p-ERK on cell proliferation, hPDLCs were incubated with PD98059, a specific ERK kinase inhibitor, and then the expression of PCNA was also analyzed by Western blot after hPDLCs were exposure to 10 %-cyclic strain at 0.1Hz-frequency for 6 hours. Result Cyclic strain increased the expression of PCNA and p-ERK1/2 in hPDLCs obviously, in which the magnitude and duration of cyclic strain had no significant difference. PD98059 could repress not only the activation of p-ERK1/2 but the expression of PCNA induced by cyclic strain in hPDLCs. Conclusion Cyclic strain promotes the proliferation of hPDLCs through ERK signaling pathway.