中文摘要：

目的探讨雌激素和维生素D对成骨细胞MC3T3-E1增殖和分化的协同调节作用及其机制。方法小鼠成骨细胞系MC3T3-E1细胞用无酚红α-MEM完全培养基培养；用MTT法检测细胞增殖率；用实时荧光定量PCR法检测干预前后MC3T3-E1细胞中细胞周期相关基因[细胞周期素E（cyclin E）、增殖细胞核抗原（PCNA）和细胞周期素依赖性激酶抑制物（Cdkn2b）]和成骨细胞分化标志物[Ⅰ型胶原（COLⅠ）、碱性磷酸酶（ALP）和骨桥蛋白（OPN）]基因的表达。ALP活性染色用BCIP／NBT显色法。结果单用雌激素17β-雌二醇（E_2）可促进MC3T3-E1细胞的增殖，尤其在生理浓度时作用最强，单用维生素D活性产物1，25-二羟维生素D_3[1，25-（OH）_2D_3]对MC3T3-E1细胞的增殖无影响，1，25-（OH）_2D_3不影响E_2对MC3T3-E1细胞的促增殖作用。E_2上调MC3T3-E1细胞中cyclinE和PCNA的表达，同时下调Cdkn2b基因的表达，1，25-（OH）_2 D_3单独应用不能影响上述基因表达的变化，也不影响E_2对上述基因的调节作用。E_2可促进MC3T3-E1细胞中分化标志物（COLI、ALP和OPN）基因的表达，加用1，25-（OH）_2 D_3后可增强此作用。结论雌激素和维生素D作为两种重要的调节骨代谢的激素，在促进成骨细胞增殖方面可能无协同作用，而在促进其分化方面可能有协同作用。

英文摘要：

Objective To assess the coordinated regulation and the molecular mechanisms of 17 β-estradiol and 1,25-dihydroxyvitamin D_3 [ 1,25-（OH）_2 D_3 1 on the proliferation and differentiation of osteoblastic MC3T3-E1 cells. Methods MC3T3-E1 cells were cultured in phenol-red free α-MEM medium supplemented with 10% FBS, MTT assay was performed to determine the effects of 1713-estradiol and 1,25-（ OH）_2 D_3 on MC3T3-E1 ceils proliferation. After cells were treated with different agents, cell cycle related genes [ cyclin E, proliferation cell nuclear antigen （ PCNA ） , and cyelin-dependent kinase inhibitor 2b （ Cdkn2b ） ] and markers of osteoblastic differentiation [ type Ⅰ collagen （ COL Ⅰ ）, alkaline phosphatase （ ALP）, osteopontin （ OPN ） ] were detected with SYBR green-based quantitative PCR. ALP activity was detected with BCIP/NBT method. Results 1713-estradiol could promote proliferation of MC3T3-E1 cells, which was accordant to its ability to increase cyclin E and PCNA and to inhibit Cdkn2b mRNA expression in MC3T3-E1 cells. However, 1,25-（OH）_2 D_3 had no effect on the proliferation of MC3T3-E1 cells and also did not enhance the proliferation of MC3T3-E1 cells stimulated by 17[3-estradiol. On the other hand, 17 β-estradiol promoted the gene expression of differentiation markers Col I , ALP, and OPN, and 1,25-（ OH ）_2 D_3 synergistically increased the expression of these genes with 17 β-estradiol. Conclusion As two of the most important hormones which regulate bone metabolism, estrogen and vitamin D may coordinately promote osteoblast differentiation, but may not regulate osteoblasts proliferation synergistically.