不同浓度雌二醇对骨髓基质细胞分化过程中Cbfα1和PPAR-γ2 mRNA表达的影响(英文)

Effect of 17 beta estradiol on the mRNA expression of core-binding factor alpha 1 and proliferator activated receptor gamma 2 in bone marrow stromal cells

背景绝经后骨质疏松的病理生理机制尚未完全阐明,研究表明骨丢失与雌激素缺乏相关,后者可导致多种细胞因子生成增加,继而引起成骨细胞和破骨细胞生成增多,骨吸收增强。雌二醇能否改变骨髓基质细胞分化过程中Cbfα1和PPAR-γ2mRNA的表达进而影响其向成骨细胞分化尚不清楚。目的研究骨髓基质细胞在向成骨细胞分化的介质中,17β-雌二醇对其核结合因子α1(Cbfα1)及过氧化物酶增殖活化受体γ2(PPAR-γ2)mRNA表达的影响,探讨雌二醇对成骨细胞生成的作用。设计非随机对照研究。地点和对象所有实验均在成都军区总医院检验科和成都百奥生物技术有限公司完成,分离骨髓基质细胞所需大鼠由成都中医药大学实验动物研究中心提供。干预1,25(OH)2D3和地塞米松诱导大鼠骨髓基质细胞向成骨细胞分化,用不同浓度[(0～1)×10-6mol/L]雌二醇对细胞分化过程进行干预。主要观察指标应用半定量RT-PCR及Northernblot技术,观察不同浓度雌二醇对骨髓基质细胞分化过程中Cbfα1及PPAR-γ2mRNA表达的影响。结果雌二醇能明显抑制骨髓基质细胞分化过程中Cbfα1mRNA的表达,雌二醇浓度为[(0～1)×10-6mol/L]时,Cbfα1mRNA的表达量从(25.0±3.3)%降至(19.8±2.2)%(t=2.62,P<0.05),(14.5±1.3)%(t=5.92,P<0.01)和(6.5±1.9)%(t=9.72,P<0.01);

BACKGROUND:Bone remodeling rate increases precipitously at menopause, which may be explained that loss of sex steroids up regulates the formation of osteoclasts and osteoblasts in the marrow by up regulating the production and action of cytokines responsible for osteoclastogenesis and osteoblastogenesis.However,the molecular mechanism of 17β estradiol(E2) on osteoblastogenesis is not clear yet .OBJECTIVE:To investigate the effects of 17β estradiol(E2) on the gene expression of core binding factor alpha 1(Cbfα1) and peroxisome proliferator activated receptor gamma 2(PPAR γ2)in rat bone marrow stromal cells exposured to the differentiation medium and to elucidate the role of E2 on osteoblastogenesis.DESIGN:A nonrandomized controlled experimental study was conducted.SETTING and PARTICIPANTS:All experiments were carried out in the Department of Laboratory,Chengdu Military Command General Hospital and Chengdu Bai'ao Biol Tech Limited Company. Three month old female SD rat weighing (200±20)g used to isolate bone marrow stromal cells was obtained from the Animal Center of Chengdu University of Traditional Chinese Medicine.INTERVENTION: Adherent bone marrow stromal cells were intervened with dexamethasome (DEX) 1×10-7 mol/L,1,25(OH)2D3 1×10-9 mol/L and different concentrations [(0-1)×10-6 mol/L] of E2.MAIN OUTCOME MEASURES: The effects of E2 on the Cbfα1 and PPAR γ2 gene expression were assayed by semiquantitative RT PCR and demonstrated by Northern blot. RESULTS: A dose dependent inhibition of the expression of Cbfα1 mRNA in bone marrow stromal cell by E2 was discovered. When examined under various concentrations of E2 [(0-1)×10-6 mol/L], the expression of Cbfα1 mRNA decreased from (25.0±3.3)%to (19.8±2.2)%(t=2.62,P< 0.05), (14.5±1.3)%(t=5.92,P< 0.01) and (6.5±1.9)%(t=9.72,P< 0.01). E2 strongly stimulated the expression of PPAR γ2 mRNA in bone marrow stromal cell from (1.75±0.5)%to (9.5±2.1)%(t=7.18,P <0.01) and (19.3±3.0)%(t=11.5,P< 0.01). Northern blot showed that the expression of Cbfα1 and PPAR γ2 mRNA in bone marrow stromal cell decreased from 4.42±0.39 to 1.88±0.16(t=12.0, P< 0.01),(1.19±0.11)(t=15.8, P< 0.01)and increased from 1.31±0.12 to 2.81±0.22 (t=10.5,P< 0.01),4.02±0.36(t=14.2,P< 0.01),respectively. The activity of Alkaline phoshatase was suppressed from (42.6±2.5) U/g to (3.6±0.7)U/g protein (t=29,P< 0.01) by E2.The amount of type Ⅰcollagen decreased significantly at higher concentrations of E2.CONCLUSION:E2 promoted bone marrow stromal cells differentiating into adipocytes and inhibited osteoblastogenesis in vitro.