双酚A对硬骨鱼性腺分化的作用机制研究

Effects of bisphenol A on gonadal sex differentiation in teleost

[目的]研究双酚A对硬骨鱼生殖腺性分化的影响并探索其作用机制。[方法]运用日本比目鱼由饲养水温决定性别的生物学特性,在鱼卵孵化后的第30天到第100天性分化敏感期内,利用27℃水温使幼鱼都分化成表型的雄性,同时给予幼鱼双酚A100μg/g的饲料。在第100天(青年期)和第300天(成年期),分别对各组比目鱼样本做病理组织切片,判断其性别和雌雄比例,通过原位杂交分析以及RT-PCR分析,探索它们的作用机制。[结果]双酚A对27℃水温饲养下的雄性比目鱼幼鱼都有雌性化诱导作用,100μg/g组成年鱼的雌性比例占57%,显著高于27℃对照组(0%);比目鱼幼鱼出生后第100天时,原位杂交分析显示,芳香化酶P450的mRNA在双酚A组的雌鱼卵巢中有明显表达,但在雄鱼精巢中不表达;而苗勒氏管抑制物质(MIS)的mRNA在双酚A组的雌鱼卵巢中不表达,却在雄鱼精巢中能见到极其明显的表达。RT-PCR实验也证实了原位杂交的结果。[结论]双酚A对日本比目鱼的生殖腺性分化有雌激素样的作用,雌性化作用的机制很可能是诱导了芳香化酶P450的mRNA表达且抑制了MIS的mRNA表达。

[ Objective] To investigate the effects of Bisphenol A （ BPA ） on gonadal sex differentiation in teleost, Japanese flounder, which exhibits temperature - dependent sex determination. [ Methods] Treatment with BPA was carried out by providing the flounder larvae with an artificial diet mixed with 100 μg/g diet at a masculinizing temperature（27℃） from 30 to 100 days after hatching. Phenotypic sex was determined at 100 （juvenile stage） and 300 dah （ adult stage） by histological observation. Sex ratio, P450arom （cytochrome P450 aromatase） and MIS （Mfillerian inhibiting substance） mRNAs expression in the genetically female flounder treated with BPA were examined by hybridization in situ and RT - PCR analyses. [ Results ] The present data showed that treatment with BPA induced feminization of the flounder larvae reared at 27℃ with female percentage of 57.0%. In situ hybridization and RT - PCR analyses showed that feminization of the larvae by BPA was accompanied by up - regulation of P450arom mRNA expression and down - regulation of MIS mRNA expression in female gonad at 100 days after hatching. [ Conclusion] BPA has estrogenic action on gonadal sex differentiation in Japanese flounder. The mechanisms may be due to the induction of P450arom mRNA expression and the suppression of MIS mRNA expression,providing the basis for public health study in EEDs.