Williams Cameron E, McNabb Nicole A, Brunell Arnold, Lowers Russell H, Katsu Yoshinao, Spyropoulos Demetri D, Kohno Satomi
Marine Biology, Grice Marine Laboratory, The Graduate School of the University of Charleston, South Carolina at the College of Charleston, Charleston, SC, USA; Hollings Marine Laboratory, Charleston, SC, USA.
Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Eustis, FL, USA.
Gen Comp Endocrinol. 2018 Sep 1;265:46-55. doi: 10.1016/j.ygcen.2017.11.019. Epub 2017 Dec 5.
Deepwater Horizon spilled over 200 million gallons of oil into the waters of the Gulf of Mexico in 2010. In an effort to contain the spill, chemical dispersants were applied to minimize the amount of oil reaching coastal shorelines. However, the biological impacts of chemically-dispersed oil are not well characterized, and there is a particular lack of knowledge concerning sublethal long-term effects of exposure. This study examined potential estrogenic effects of CWAF, Corexit 9500-enhanced water-accommodated fraction of oil, by examining its effect on estrogen receptors and sex determination in the American alligator, Alligator mississippiensis. The alligator exhibits temperature-dependent sex determination which is modulated by estrogen signals, and exposure to 17β-estradiol (E) and estrogenic compounds in ovo during the thermosensitive period of embryonic development can induce ovarian development at a male-producing temperature (MPT). CWAF induced transactivation up to 50% of the maximum induction by E via alligator estrogen receptors in vitro. To determine potential endocrine-disrupting effects of exposure directly on the gonad, gonad-adrenal-mesonephric (GAM) organ complexes were isolated from embryos one day prior to the thermosensitive period and exposed to E, CWAF, or medium alone in vitro for 8-16 days at MPT. Both CWAF and E exposure induced a significant increase in female ratios. CWAF exposure suppressed GAM mRNA abundances of anti-Müllerian hormone (AMH), sex determining region Y-box 9, and aromatase, whereas E exposure suppressed AMH and increased Forkhead box protein L2 mRNA abundances in GAM. These results indicate that the observed endocrine-disrupting effects of CWAF are not solely estrogenically mediated, and further investigations are required.
2010年，“深水地平线”号向墨西哥湾水域泄漏了超过2亿加仑的石油。为了控制泄漏，使用了化学分散剂以尽量减少到达沿海岸线的石油量。然而，化学分散油的生物影响尚未得到充分表征，尤其缺乏关于暴露的亚致死长期影响的知识。本研究通过研究其对美国短吻鳄（密西西比鳄）雌激素受体和性别决定的影响，考察了化学分散油增强水溶组分（CWAF）的潜在雌激素效应。短吻鳄表现出温度依赖型性别决定，这受雌激素信号调节，在胚胎发育的热敏期，卵内暴露于17β-雌二醇（E）和雌激素化合物可在雄性产生温度（MPT）下诱导卵巢发育。在体外，CWAF通过短吻鳄雌激素受体诱导的反式激活高达E最大诱导的50%。为了确定直接暴露于性腺的潜在内分泌干扰效应，在热敏期前一天从胚胎中分离出生殖腺-肾上腺-中肾（GAM）器官复合体，并在MPT下于体外将其暴露于E、CWAF或单独的培养基中8 - 16天。暴露于CWAF和E均导致雌性比例显著增加。暴露于CWAF会抑制GAM中抗苗勒管激素（AMH）、性别决定区Y盒9和芳香化酶的mRNA丰度，而暴露于E会抑制GAM中的AMH并增加叉头框蛋白L2的mRNA丰度。这些结果表明，观察到的CWAF的内分泌干扰效应并非仅由雌激素介导，需要进一步研究。
