Abstract：
Nodularin is a potent cyanotoxin that has been detected in aquatic environments as well as in the body of aquatic organisms throughout the world, but its effects on the reproductive system are yet to be explored. The present study investigated the toxic effects of environmentally relevant concentrations of nodularin on the reproductive endocrine system of female zebrafish (Danio rerio). After exposure to nodularin for 14 days, decreased gonadosomatic Index (GSI), germinal vesicle breakdown (GVBD), and decreased level of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17β-estradiol (E2) level and increased testosterone (T) content in female zebrafish suggested that nodularin may disrupt both oocyte growth and maturation. In support of this data, alteration in different marker gene expression on the hypothalamic-pituitary-gonadal-liver (HPGL) axis was observed. Transcriptional levels of genes related to steroidogenesis including cytochrome P450 aromatase (cyp19a1a) in the ovary and primary vitellogenin genes (vtg1, vtg2, and vtg3) in the liver were down-regulated and marker genes for oxidative stress (sod, cat, and gpx) were up-regulated on HPGL axis. These findings revealed for the first time that nodularin is a potent endocrine-disrupting compound posing oxidative stress and causes reproductive endocrine toxicity in female zebrafish, emphasizing the importance of assessing its environmental risks.
摘要：
Nodularin是一种强效的蓝藻毒素，已在水生环境以及世界各地的水生生物体内检测到，但是它对生殖系统的影响还有待探索。本研究调查了环境相关浓度的nodularin对雌性斑马鱼（Daniorerio）生殖内分泌系统的毒性作用。暴露于nodularin14天后，性腺指数降低（GSI），生发囊泡分解（GVBD），促卵泡激素（FSH）水平降低，黄体生成素(LH),雌性斑马鱼中17β-雌二醇（E2）水平和睾丸激素（T）含量增加表明结节素可能会破坏卵母细胞的生长和成熟。为了支持这些数据，观察到下丘脑-垂体-性腺-肝（HPGL）轴上不同标记基因表达的变化。与类固醇生成相关的基因的转录水平，包括卵巢中的细胞色素P450芳香化酶（cyp19a1a）和肝脏中的原代卵黄蛋白原基因（vtg1，vtg2和vtg3）被下调，并且是氧化应激的标记基因（sod，猫,和gpx)在HPGL轴上上调。这些发现首次揭示了nodularin是一种强效的内分泌干扰化合物，引起氧化应激，并引起雌性斑马鱼的生殖内分泌毒性，强调评估其环境风险的重要性。
