中文摘要：

目的：研究不同大小机械牵张力对成骨细胞OPG／RANKL表达的影响。方法：通过自制多通道细胞牵张应力加载系统对小鼠成骨样细胞MC3T3-E1同时施加0％、6％、12％和18％的机械牵张力，作用24h后，用RT-PCR方法检测细胞受力后OPGmRNA／RANKL mRNA表达的变化，用免疫印迹法（Western Blotting）检测其蛋白表达的变化。结果：细胞受力后，其OPG mRNA及蛋白表达随牵张力值的增大明显增加，而RANKL mRNA及蛋白表达随牵张力值的增大明显减少。结论：不同大小机械牵张力可以影响成骨细胞的OPG／RANKL表达，进而影响正畸骨改建。

英文摘要：

Objective To investigate the effects of different magnitudes of mechanical strain on expression of osteoprotegerin （OPG）/ receptor activator of nuclear factor-kB ligand （RANKL） in osteoblasts in vitro. Methods MC3T3-E1 cells were subjected to 0%,6%, 12% or 18% elongation by using multi-passage cell stress loading system simultaneously for 24h, then OPG/RANKL mRNA and protein expression in MC3T3-E1 cells were detected by reversetranscription polymerase chain reaction （RT-PCR） and Western blotting, respectively. Results The expression of OPG in MC3T3-E1 cells significantly increased in groups under strain （6%, 12%,18% elongation） in magnitude-dependent manner compared to control （0%） after mechanical strain treatment for 24h , whereas the expression of RANKL significantly decreased in groups under strain （6%, 12%, 18% elongation） in magnitude-dependent manner compared to control （0%）. Conclusion These results indicated that different magnitudes of mechanical strain affected expression of OPG/RANKL in MC3T3-E1 cells in magnitude-dependent manner, which profoundly affect bone remodeling.