中文摘要：

目的：探索机械牵张应力对人成骨肉瘤细胞MG-63中RhoA／ROCK信号通路的影响。方法：将同一条件培养的细胞MG-63分为实验组（加力）与对照组（不加力），实验组采用Flexcell牵张应力加裁系统，选择12％形变率作为加载应力值，分为五个时间组，分别加载1h，4h，8h，12h，24h，RT-PCR检测RhoA、ROCKmRNA水平表达的变化，Western-Blot检测RhoA与Rock蛋白含量变化。结果：RT-PCR显示MG-63细胞受应力刺激后1hRhoA、ROCK均未见明显变化（P〉0．05），4小时后略有升高（P〈0．05），在8h达到最大值（P〈0．05），12、24h降低，但仍高于对照组（P〈0．05）；Western-Blot显示MG-63细胞受应力刺激后1hRhoA、ROCK均未见明显变化，4h仍未见明显变化，在8h达到最大值，12、24h降低，高于对照组。结论：机械牵张力加载下MG-63细胞内RhoA、ROCK表达升高并随时间增加出现峰值，提示其可能在成骨细胞力学信号转导过程中发挥重要作用。

英文摘要：

Objective： To investigate the effects of mechanical strain on RhoA and ROCK expression in osteoblasts MG-63. Methods： Mechanical strain at 12 % was applied to MG-63 cells for 0（control group）, 1, 4, 8, 12 and 24 hours respectively in vitro. RhoA and ROCK mRNA expression in the cells was examined by RT-PCR, RhoA and ROCK expressions were examined by Western Blot. Results： RT-PCR showed that mRNA expressions Of RhoA and ROCK were not significantly changed after 1 h strain treatment（P〉0.05） and slightly increased within 4 hours of mechanical strain application. Then the expression rose to the highest value after 8 hours and decreased after 12 and 24 hours （P〈0.05）. Western Blot represented a similar result. The protein expression was changed and up to the top after 8 hours then decreased gradually after 12 and 24 hours （P〈0.05）. Conclusion： Mechanical strain elongation regulates RhoA and ROCK expression of MG-63 cells and the expression was up to a maximum value with the increase of time. It was speculated that RhoA and ROCK may play an important role in cell signal transduction of mechanical strain.