Objective To investigate the relationship between c-fos gene and filamentous actin (F-actin) in MG-63 osteoblasts under cyclic tensile stress. Methods MG-63 osteoblasts were subjected to cyclic tensile stress (0.5 Hz, 2 000 (xstrain) for 3, 6, and 12 h. The changes of c-fos gene were investigated by fluorescent quantitation polymerase chain reaction. Then the best loading time group was screened as the experimental group compared with 0 h group. The changes of F-actin and c-fos were investigated with or without cytochalasin D treatment. Results Cyclic tensile stress induced high expression of c-fos mRNA, and peaked at 3 h. After loading, F-actin had a structure reorganization, but had no change in expression. After cytochalasin D treatment, the formation of stress fibers and the fluorescence intensity of F-actin cytoskeleton significantly reduced, meanwhile the c-fos mRNA expression was inhibited. Conclusion After loading, there is only structure reorganization for F-actin, and the expression has not any change. That means the remodeling F-actin is the existing one. F-actin reorganization is an important part in c-fos gene expression induced by stress.%目的 探讨成骨样细胞MG-63中c-fos基因和细胞骨架丝状肌动蛋白(F-actin)的相互关系.方法 对MG-63细胞施加周期性张应力,频率为0.5 Hz,细胞应变为2000 μstrain,按3、6、12h不同时间段进行加载,采用荧光定量聚合酶链反应(PCR)检测c-fos mRNA的变化,筛选最佳加载时间点,并作为实验组和0h组进行对比,检测在细胞松弛素D作用下c-fos mRNA和F-actin的表达变化.结果 周期性张应力可以诱导c-fos mRNA的表达增加,至3h达到峰值；在周期性张应力作用下,MG-63细胞中F-actin的结构、排列发生改变,但荧光强度无明显变化；经细胞松弛素D处理后,张应力作用下的MG-63细胞的应力纤维明显减少,F-actin荧光强度降低,c-fos mRNA表达受抑制.结论 周期性张应力作用下,F-actin的量并没有明显变化,只是出现了结构上的重组,且重组的是既有的F-actin.F-actin重组是应力诱导c-fos基因高表达的一个重要环节.
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