title: Microcystin-LR impairs zebrafish reproduction by affecting oogenesis and endocrine system.
abstract: 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.
authors.affiliation: 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.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: 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. Electronic address: lqxie@niglas.ac.cn.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Xie
authors.affiliation: Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, PR China. Electronic address: yanyunjun@hust.edu.cn.
authors.forename: Yunjun
authors.initials: Y
authors.lastname: Yan
mesh_terms: D000818:Animals; D004703:Endocrine System / Q000187:drug effects*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000235:genetics / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D009866:Oogenesis / Q000187:drug effects*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D012098:Reproduction / Q000187:drug effects*; D014819:Vitellogenins / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000254:growth & development* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D012739:Gonadal Steroid Hormones; D008387:Marine Toxins; D052998:Microcystins; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D029961:Zebrafish Proteins; C448022:gonadotropin-releasing hormone-III; D007987:Gonadotropin-Releasing Hormone; C057862:cyanoginosin LR; D011761:Pyrrolidonecarboxylic Acid
keywords: Hypothalamic–pituitary–gonad axis; Microcystin-LR; Oocyte growth; Reproductive toxicity; Trans-generational effects