周期性张、压应力作用下人牙周膜干细胞RANKL/OPG的变化

Changes of RANKL/OPG in hPDLSCs under the Cyclic Tensile/Compressive Stress

目的:对周期性张、压应力作用下人牙周膜干细胞(h PDLSCs)RANKL、OPG及RANKL/OPG比值的变化进行初步探讨。方法:用3 000μstrain,0.5 Hz的周期性张、压应力对h PDLSCs分别加载0(对照组)、3、6、12、24 h。Western blotting检测RANKL和OPG的变化,计算RANKL/OPG比值的变化。结果:周期性张应力作用3 h,RANKL/OPG比值达到最低点(0.902±0.196),显著低于对照组水平(P=0.000),此后开始上升,但直到24 h,仍低于对照组水平。周期性压应力作用3 h,RANKL/OPG比值达到最高点(1.058±0.147),显著高于对照组水平(P=0.000),6 h(0.996±0.103)回落到对照组水平(P=0.152),此后直到24 h(0.8449±0.041),显著低于对照组水平(P=0.000)。结论:周期性张、压应力都可以上调h PDLSCs的RANKL和OPG表达。在周期性张应力加载的最初24 h,h PDLSCs不能促进破骨细胞分化;而周期性压应力加载的最初6 h,h PDLSCs可以促进破骨细胞分化,此后转而抑制破骨细胞分化。

Objective： The aim of the present study is to investigate the changes of RANKL, OPG and the RANKL/OPG ratio derived from human periodontal ligament stem cells （hPDLSCs） under the stress stimulation. Methods： 3000 μstrain cyclic tensile/compressive stress were applied to hPDLSCs for 0 h （control group）, 3 h, 6 h, 12 h, and 24 h. Western blotting was used to detect the protein changes of RANKL and OPG, and the RANKL/OPG ratios were then calculated. Results： Both RANKL and OPG were up-regulated under the cyclic tensile and compressive stress. Under the cyclic tensile stress, RANKL/OPG ratio was significantly decreased to the lowest level （0.902 ± 0.196） （P = 0.000） at 3 h, and was gradually increasing thereafter, but did not reach to that at 0 h, until 24 h. Under the stimulation of cyclic compressive stress, RANKL/OPG ratio was up-regulated to the peak （1.058 ± 0.147） （P = 0.000） at 3 h, returned to the level of the control group at 6 h （0.996 ± 0.103） （P = 0.152）, and became significantly lower than that of control group at 12 h and 24 h （P = 0.000）. Conclusion： Both tensile and compressive stress could up-regulate the expression of RANKL and OPG in hPDLSCs. During the first 24 h of cyclic tensile stress loading, hPDLSCs could not promote the process of osteoclastogenesis. During the cyclic compressive stress loading, hPDLSCs promoted the process of osteoclastogenesis in the first 6 h, and inhibited the process of osteoclastogenesis thereafter.