【摘要】 目的研究大豆苷原(daidzein,DA)对成骨细胞雌激素受体(estrogen receptor,ER)和过氧化物酶体增殖物激活受体γ(peroxisome proliferator-activated receptorγ,PPARγ)表达的调节作用,并观察雌激素对这种调节的影响。方法小鼠成骨细胞MC3T3-E1体外低血清(α-MEM,含2%FBS)培养,分别用0.1和10μmol/L的DA处理,采用实时定量PCR或Western blot分析细胞ERα、ERβ和PPARγ的表达变化。加入浓度均为0.1μmol/L的ER拮抗剂ICI182780或PPARγ拮抗剂GW9662,观察ER和PPARγ在DA调节中的作用。为观察雌激素的影响,采用无血清培养,在10nmol/L 17β-雌二醇(E2)条件下研究DA对细胞受体表达的作用。结果 DA抑制体外培养成骨细胞ER表达,而刺激其PPARγ表达。0.1和10μmol/L的DA分别下调ERα蛋白水平44%和38%(P<0.05),下调ERβ蛋白水平50%(P<0.05)和31%(P<0.05),上调PPARγ74%和78%(P<0.05)。ICI182780可阻断DA对ERα转录水平的抑制作用,DA对成骨细胞ERβmRNA水平的下调无统计学意义(P=0.087 4);GW9662可阻断DA对PPARγ表达的上调作用,提示成骨细胞ER和PPARγ参与自身表达调节。在10nmol/L 17β-雌二醇条件下,DA对无血清培养的成骨细胞ERα转录水平的抑制作用由28.0%～29.6%(P<0.05)增强至74.0%～82.8%(P<0.01),其对ERβ表达的抑制作用也明显增强,而对PPARγ的上调作用几乎丧失。结论 DA可通过调节ERs和PPARγ等受体表达间接影响成骨细胞的药物反应,雌激素可明显影响DA的受体调节作用。DA对细胞受体表达的调节作用可能是其对成骨细胞时间相关双相调节的重要机制之一。更多还原

【Abstract】 Objective To explore the effects of daidzein(DA) on the expressions of estrogen receptors(ER) and peroxisome proliferator-activated recepor γ(PPARγ) in osteoblasts and the influence of estrogen on these effects. Methods A mouse osteoblastic cell line MC3T3-E1 cultured in α-MEM containing 2% FBS was treated by 0.1 and 10 μmol/L DA.ER antagonist ICI182780 and PPARγ antagonist GW9662 in 0.1 μmol/L was added as required,and an equivalent amount of phosphate buffer solution(PBS) was used as control.For the study on estrogen effect,the cells were treated by DA in the serum-free medium with or without 10 nmol/L 17β-estradiol(E2).The expressions of ERα,ERβ and PPARγ were determined by real-time RT-PCR and Western blot analysis,respectively. Results DA inhibited ER,expression but stimulated PPARγ expression in the cells at the concentration of 0.1 and 10 μmol/L.The down-regulation of ERα by DA could be blocked by ICI182780,whereas the up-regulation of PPARγ could be repressed by GW9662 in transcription levels.Furthermore,the inhibitory effect of DA on ERβ expression was markedly enhanced,while its stimulatory effect on PPARγ expression was almost lost in serum-free medium with 10 nmol/L 17β-estradiol as determined by real-time RT-PCR. Conclusions Besides its direct roles in ERs and PPARγ mediated gene transcriptions,DA could exert indirect effect on cellular pharmacological responses by altering ER and PPARγ expressions.The predominant influence on receptors expression probably involved in the time-related biphasic effects of DA on osteogenesis,which was supposedly influenced by estrogen level.更多还原