中文摘要：

目的：观察不同剂量糖皮质激素（GC）对体外培养成骨细胞活性、分化的影响以及牛膝活性成分8蜕皮甾酮（B—Ecd）的干预作用，以探讨GC引起骨质疏松的部分机制。方法：由骨髓基质细胞分化培养成骨细胞，用地塞米松（Dex）以不同剂量不同作用时间处理细胞，MTT法测定细胞活性后，将细胞分为7组：正常对照组、1×10^-5mol／LGC模型组、GC＋10^-5mol／LRU486组、GC＋10^-5mol／L阿仑膦酸钠（ALN）组、GC＋10^-5mol]LB—Ecd组、GC＋10^-6mol／LB—Ecd组、GC＋10^-7mol／L13-Ecd组。RealtimePCR检测相关基因mRNA表达，WesternBlot检测β—catenin蛋白表达。结果：小剂量浓度Dex（≤10^-8mol／L）有促进成骨细胞活性的趋势，而超生理剂量的Dex贝0抑制细胞的分化与活性。GC模型组GR、RunX2、OP-1、ALPmRNA表达下降（P〈0．05），10^-5、10^-6、10^-7mol／LD—Ecd能不同程度干预细胞降低的基因mRNA表达水平。Gc模型组细胞β—catenin蛋白表达升高（P〈0．05），10^-5mol／Lβ3-Ecd能抑NGC对细胞的影响。结论：超生理剂量GC抑制体外培养成骨细胞的分化与涪眭，可能与介导Wnt／B—catenin信号途径有关；一定剂量6蜕皮甾酮则能不同程度地干预糖皮质激素对成骨细胞的影响。

英文摘要：

Objective： To observe the effect of different doses of glucocorticoid on osteoblasts activity and differentiation and to explore the effect of β-Ecdysone （β-Ecd） on osteoblasts induced by excess glucocorticoid. Methods： Osteoblasts were cultured from bone marrow stem cells, then treated by dexamethasone with different doses and times. Cells activity was measured by MTT, then divided into 7 groups： Control, GC 10-5mol/L, GC with RU486 10-5mol/L, GC with alendronate （ALN） 104mol/L, GC with 104mol/L β-Ecd, GC with 10-6mol/L β-Ecd, GC with 10-Tmol/L β-Ecd. The related genes mRNA expressions were detected by Real time PCR, and β-catenin expression detected by Western Blot. Results： Low dose of Dex （ ≤ 10-8mol/L） promoted the activity of osteoblasts, while higher than physiological dose inhibited the cells. 10-Smol/L Dex lowered GR, RunX2, OP-1, ALP mRNA expressions （P〈0.05）, 10-Smol/L, 10-6mol/L, 10-Tmol/L β-Ecd reversed them in varying degrees. 10-Smol/L Dex increased β-catenin expression （P〈0.05）, 104mol/L β-Ecd could interfere with it. Conclusion： The results show that high dose of GC inhibited osteoblasts in part through mediating the Wnt signal pathway. The β-Ecdysone could reverse the inhibition of osteoblasts activity and differentiation induced by Dexamethasone.