Bioaccumulation, metabolism and endocrine-reproductive effects of metolachlor and its S-enantiomer in adult zebrafish (Danio rerio)
Bioaccumulation, metabolism and endocrine-reproductive effects of metolachlor and its S-enantiomer in adult zebrafish (Danio rerio)
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DOI：
10.1016/j.scitotenv.2021.149826
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发表时间：
2021-08-27
影响因子：
9.8
通讯作者：
Ma, Hongju
中科院分区：
文献类型：
--
作者：
Ou-Yang, Kang;Feng, Tangqi;Ma, Hongju
本研究的目的是评价异丙甲草胺和s -异丙甲草胺在斑马鱼体内的对映选择性生物积累、代谢和毒性作用。将5月龄斑马鱼分别暴露于异甲草胺和S-异甲草胺28 d，然后转移到清水中净化7 d。在吸收阶段，S-异甲草胺在低浓度下优先积累，而在高浓度下优先积累。两种化学物质第一天在斑马鱼体内代谢率均为bbb70 %，代谢过程相同。在积累终点，s -甲草胺对斑马鱼的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽s -转移酶（GST）活性及发育指标均无显著抑制作用。300 μ g/L的异丙甲草胺显著抑制肝脏SOD、CAT和GST酶活性，影响肝脏发育。异甲草胺在高浓度下优先富集可能是其对斑马鱼具有较高毒性的原因。进一步研究表明，异丙甲草胺显著改变下丘脑-垂体-性腺（HPG）轴相关基因gnrh2、gnrh3、lh/3、17/3hsd和cyp19a的表达，从而降低女性睾酮(T)水平和男性性激素（雌二醇和睾酮）水平。s-甲草胺通过改变HPG轴相关基因fsh/3、cyp17、17/3hsd和cyp19a的表达，提高雌鼠E2水平。异丙甲草胺和s -异丙甲草胺对斑马鱼内分泌干扰的作用机制不同，可能具有性别特异性。将暴露的斑马鱼置于洁净水中7天后，大部分酶活性、性激素水平及相关基因表达水平恢复正常，这可能与两种化学物质的快速代谢有关。(c) 2021 Elsevier B.V.版权所有
The aim of the present study was to evaluate the enantioselective bioaccumulation, metabolism, and toxic effects of metolachlor and S-metolachlor in zebrafish. Five-month-old zebrafish were exposed to metolachlor and S- metolachlor for 28 days, then transferred to clean water and purified for 7 days. In the uptake phase, S- metolachlor was preferentially accumulated at low concentrations, while metolachlor was preferentially accu-mulated at high concentrations. The two chemicals were metabolized by >70% in zebrafish on the first day and showed same metabolic process. At the accumulation endpoint, S-metolachlor had no significant inhibitory effect on the enzymes activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and developmental indicators of zebrafish. However, 300 mu g/L metolachlor significantly inhibited the en-zymes activities of SOD, CAT and GST and affected the liver development. The preferential enrichment of metolachlor at the high concentration may be the reason for its higher toxicity to zebrafish. Further research demonstrated that metolachlor significantly altered the expression of hypothalamic-pituitary-gonadal (HPG) axis-related genes, including gnrh2, gnrh3, lh/3, 17/3hsd and cyp19a, thereby reducing the levels of testosterone (T) in females and sex hormones (estradiol and testosterone) in males. S-metolachlor increased the levels of es-tradiol (E2) in females by altering the expression of HPG axis-related genes such as fsh/3, cyp17, 17/3hsd and cyp19a. The mechanism of metolachlor and S-metolachlor on the endocrine disrupting effects of zebrafish is dif-ferent, which may be sex-specific. 7 days after transferring the exposed zebrafish to clean water, most of the en-zymes activities, sex hormone levels and related gene expression levels returned to normal, which may be related to the rapid metabolism of the two chemicals. (c) 2021 Elsevier B.V. All rights reserved.