金雀异黄素对雄性斑马鱼卵黄原蛋白mRNA的诱导机理

Induction Mechanism of Genistein on Vtg mRNA in Male Zebrafish( Danio rerio)

采用质量浓度分别为1、10、100、1 000μg/L的金雀异黄素对成年雄性斑马鱼进行水体暴露28 d,通过real-time PCR技术检测雄性斑马鱼肝脏内Vtg-1（卵黄原蛋白）、ERα和ERβ1 mRNA（雌激素受体）的表达水平,并利用同位素放射免疫法检测雄性斑马鱼性腺w（睾酮）和w（E2）（E2为17β-estradiol,17β-雌二醇）.结果表明：10-1 000μg/L金雀异黄素显著诱导了雄性斑马鱼肝脏Vtg-1 mRNA的表达,二者呈剂量-效应关系,同时显著上调了雌激素受体ERβ1 mRNA的表达;但1-1 000μg/L金雀异黄素却极显著地抑制了雄性斑马鱼肝脏内ERαmRNA的表达,同时造成雄性斑马鱼性腺w（E2）的升高和w（睾酮）的降低.研究结果显示,金雀异黄素可能通过提高雄性斑马鱼体内ERβ1mRNA的表达和内源w（E2）,增强ERβ1对内源雌激素的介导作用,从而促进Vtg-1的表达.

Fish species are being threaten by the high concentration of geuistein in water bodies. It is urgent to explore the estrogenic effects and the mechanisms of genistein for aquaculture development and fishery resources protection. Mature individuals of male zebrafish were exposed to a range of concentrations of genistein （1, 10, 100, 1000 μg/L） for 28 days. The study was performed using real-time PCR as a readout to quantify the change in vitellogenin （ Vtg-1 ） mRNA levels. ERα and ERβ1 mRNA levels were then quantified by real- time PCR to explore the action mechanism of genistein. Meanwhile, radioimmunoassay was used to detect the change of E2 （17β-estradiol） and testosterone levels in gonad of male individuals. The results showed that exposures to 10-1000 μg/L genistein led to dose-dependent increase in Vtg-1 mRNA. The transcriptions of ERβ1 mRNA were significantly stimulated, while the transcriptions of ERa mRNA were significantly inhibited when exposed to 1-1000 μg/L genistein. In addition, genistein treatments enhanced the levels of E2 and reduced the testosterone levels. The results suggest that genistein may enhance the synthesis of Vtg through increasing endogenous E2 and ERβ1 levels and thus improve the mediation of ERβ1 for endogenous E2.