State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, PR China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, PR China.
Chemosphere. 2015 Feb;120:115-22. doi: 10.1016/j.chemosphere.2014.06.028. Epub 2014 Jul 9.
Previous studies have shown that microcystins (MCs) are able to exert negative effects on the reproductive system of fish. However, few data are actually available on the effects of MC-LR on the reproductive system of female fish. In the present study, female zebrafish were exposed to 2, 10, and 50 μg L(-1) of MC-LR for 21 d, and its effects on oogenesis, sex hormones, transcription of genes on the hypothalamic-pituitary-gonad (HPG) axis, and reproduction were investigated for the first time. It was observed that egg production significantly declined at ⩾ 10 μg L(-1) MC-LR. MC-LR exposure to zebrafish increased the concentrations of 17β-estradiol (E2) and vitellogenin (VTG) at 10 μg L(-1) level, whereas concentrations of E2, VTG and testosterone declined at 50 μg L(-1) MC-LR. The transcriptions of steroidogenic pathway gene (cyp19a, cyp19b, 17βhsd, cyp17 and hmgra) changed as well after the exposure and corresponded well with the alterations of hormone levels. A number of intra- and extra-ovarian factors, such as gnrh3, gnrhr1, fshβ, fshr, lhr, bmp15, mrpβ, ptgs2 and vtg1 which regulate oogenesis, were significantly changed with a different dose-related effect. Moreover, MC-LR exposure to female zebrafish resulted in decreased fertilization and hatching rates, and may suggest the possibility of trans-generational effects of MC-LR exposure. The results demonstrate that MC-LR could modulate endocrine function and oogenesis, eventually leading to disruption of reproductive performance in female zebrafish. These data suggest there is a risk for aquatic population living in MC polluted areas.
先前的研究表明，微囊藻毒素（MCs）能够对鱼类的生殖系统产生负面影响。然而，实际上关于 MC-LR 对雌性鱼类生殖系统的影响的数据很少。在本研究中，雌性斑马鱼暴露于 2、10 和 50μg/L 的 MC-LR 中 21 天，首次研究了其对卵发生、性激素、下丘脑-垂体-性腺（HPG）轴上基因的转录以及繁殖的影响。结果观察到，在 ⩾10μg/L MC-LR 时产卵量显著下降。MC-LR 暴露于斑马鱼中，在 10μg/L 水平上增加了 17β-雌二醇（E2）和卵黄蛋白原（VTG）的浓度，而在 50μg/L MC-LR 时 E2、VTG 和睾丸激素的浓度下降。暴露后类固醇生成途径基因（cyp19a、cyp19b、17βhsd、cyp17 和 hmgra）的转录也发生了变化，与激素水平的变化相吻合。许多调节卵发生的卵巢内和卵巢外因素，如 gnrh3、gnrhr1、fshβ、fshr、lhr、bmp15、mrpβ、ptgs2 和 vtg1，均发生了显著变化，且具有不同的剂量相关效应。此外，MC-LR 暴露于雌性斑马鱼导致受精和孵化率降低，这可能表明 MC-LR 暴露存在跨代效应的可能性。结果表明，MC-LR 可以调节内分泌功能和卵发生，最终导致雌性斑马鱼生殖性能受损。这些数据表明，生活在 MC 污染地区的水生种群存在风险。
