中文摘要：

目的：观察机械牵张应力作用下人成骨肉瘤细胞MG-63中丝切蛋白（Cofilin）的表达。方法：将MG-63细胞分为加力组与对照组（不加力），加力组采用Flexcell牵张应力加载系统，用12％变形率的应力值进行力学刺激1、4、8、12、24h，用免疫荧光染色观察Cofilin的变化，RT-PCR检测CofilinmRNA水平含量的变化，Western-Blot测定细胞内Cofilin蛋白含量。结果：MG-63细胞受应力刺激后1、4h细胞内Cofilin染色逐渐增强，8、12、24h细胞染色逐渐减弱，但仍高于对照组。应力作用下CofilinmRNA水平无明显变化（P〉0．05）。WesternBlot显示，加载后1h细胞内Cofilin含量增高（P〈0．05），4h时达到高峰（P〈0．05），8、12、24h后Cofilin含量逐渐减少，但仍高于对照组（P〈0．05）。结论：机械牵张应力刺激可明显上调Coil-lin在MG-63细胞中表达，且具有时间依赖性，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 cofilin expression in MG-63 osteoblastic cells. Methods： Mechanical strain at 12% was applied to MG-63 ceils for 0（ control group）, 1,4,8,12 and 24 hours respectively in vitro. Cofilin mR- NA expression in the ceils was examined by RT-PCR, cofilin protein expression was examined by immunofluoresence assay and West- ern Blotting. Results： The fluorescence intensity of the cells was enhanced from 1 to 4 hours after strain treatment, then decreased from 8 to 24 hours, mRNA was not significantly changed after stain treatment（P 〉 0.05 ）. Western blotting showed that cofilin expres- sion level in MG-63 cells was gradually increased within the first 4 hours of mechanical strain application （ P 〈 0.05 ）, then decreased in 8, 12 and 24 hours （P 〈0.05 ） ,but still higher than that in the control ceils. Conclusion： Mechanical strain elongation regulates cofilin expression of MG-63 cells. Cofilin may plays an important role in cell signal transduction of mechanical strain.