【摘要】 为探讨地塞米松 (dexamethasone ,DEX)抑制成骨细胞分化的机制 ,观察了不同浓度DEX对体外培养大鼠成骨细胞的碱性磷酸酶活性、骨钙素 (osteocalcin ,OC)合成、Ⅰ型胶原蛋白表达的影响 ,并用RT PCR方法检测了成骨细胞中LIM矿化蛋白 1mRNA的表达量。结果显示 :低浓度 ( 10 -9mol/L)的DEX能增强碱性磷酸酶的活性、OC的分泌和Ⅰ型胶原蛋白的表达 ;而高浓度 ( 10 -7mol/L)的DEX对它们则起抑制作用 ,并下调成骨细胞正调节因子LMP 1mRNA的表达。上述结果表明 ,低浓度的DEX促进成骨细胞的分化 ;高浓度的DEX则抑制成骨细胞的分化 ,其抑制作用可能是通过下调LMP 1mRNA的表达而实现的更多还原

【Abstract】 To investigate the mechanisms of the inhibition of osteoblastic differentiation by dexamethasone (DEX), the effects of different doses of DEX on the activity of alkaline phosphatase (ALP), the synthesis of osteocalcin (OC) and the expression of colaggen type Ⅰ were observed in the cultured rat osteoblasts. The LIM mineralization protein 1 (LMP 1) mRNA, a positive regulator of osteoblasts, was semi quantified by RT PCR. The results showed that a lower dose (10 -9 mol/L) of DEX could enhance the activity of ALP, the synthesis of OC and the expression of collagen type Ⅰ. However, a higher dose (10 -7 mol/L) of DEX inhibited them and down regulated the expression of LMP 1 mRNA in osteoblasts. It is suggested that DEX stimulates osteoblast differentiation at lower dose, while at higher dose it inhibits osteoblast differentiation. The inhibitory action of DEX on osteoblast differentiation might be mediated by the down regulation of LMP 1 mRNA.更多还原