17β-雌二醇对骨髓基质细胞骨形态发生蛋白受体ⅠA、B mRNA表达的影响

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(E₂)对其骨形态发生蛋白受体(BMPR)ⅠA,ⅠBmRNA表达的影响,探讨雌二醇对成骨细胞生成的作用。方法:用1,25(OH)₂D₃和地塞米松(DEX)诱导大鼠骨髓基质细胞向成骨细胞分化,应用半定量RT-PCR技术,观察不同浓度E₂对骨髓基质细胞分化过程中BMPR-ⅠA,ⅠBmRNA表达的影响,以α-磷酸奈酚为底物测定细胞碱性磷酸酶的活性,VanGieson染色法显示Ⅰ型胶原的含量。结果:E₂能明显抑制骨髓基质细胞分化过程中BMPR-ⅠAmRNA的表达,且呈剂量依赖性,随E₂浓度增加,BMPR-ⅠAmRNA从(23.7±1.7)%降至(16.3±1.5)%(P<0.05)和(8.3±1.2)%(P<0.01);BMPR-ⅠBmRNA随E₂浓度增加而增加,从(1.3±0.6)%增至(5.7±2.0)%(P<0.05)和(15.3±3.0)%(P<0.01)。ALP活性随E₂浓度增加而降低,从(42.6±2.5)U·L^-1·g^-1protein降至(10.8±1.5)U·L^-1·g^-1protein和(3.6±1.7)U·L^-1·g^-1protein(P<0.01);细胞Ⅰ型胶原的含量随E₂浓度增加而减少。结论:E₂能明显抑制体外培养的骨髓基质细胞分化过程中BMPR-ⅠAmRNA的表达,降低成骨细胞生成。

Effect of 17β-estradiol on the BMPR-ⅠA,ⅠB gene expression in bone marrow stromal cells

AIM: To investigate the effects of 17β-estradiol (E₂) on the gene expression of typeⅠA and typeⅠB bone morphogenetic protein receptor (BMPR-ⅠA,ⅠB) in rat bone marrow stromal cells exposured to the differentiation medium and to elucidate the effects of E₂ on osteoblastogenesis. METHODS: Adherent bone marrow stromal cells were cultured in differentiation medium containing DEX(10^-7 mol·L^-1)and 1,25(OH)₂D₃ (10^-9mol·L^-1)and different concentrations of E₂. The gene expression of BMPR-ⅠA, ⅠB was quantified by semiquantitative RT-PCR. RESULTS: E₂ evidently inhibited the expression of BMPR-ⅠA mRNA in bone marrow stromal cells.The suppression was dose-dependent. When examined under various concentrations of E₂ (0-10^-6mol·L^-1), the expression of BMPR-ⅠA mRNA were decreased from (25.7±2.5)% to(16.3±1.5)%(P＜0.05)and(8.3±1.2)%(P＜0.01). E₂ stimulated the expression of BMPR-ⅠB mRNA by 4- to 10-fold above the control. The activity of alkaline phosphatase (ALP) was decreased significantly at higher concentrations of E₂,from(42.6±2.5) to (17.9±2.0), (10.8±1.5) and (3.6±0.7)U·L^-1·g^-1protein(P＜0.01). The amount of type Ⅰcollagen was suppressed by E₂. CONCLUSION: E₂ suppresses the gene expression of BMPR-ⅠA in bone marrow stromal cells and inhibits osteoblastogenesis in vitro.