Endocrine disrupting effects of tebuconazole on different life stages of zebrafish (Danio rerio). (June 2019)

• Record Type: Journal Article
• Authors: Li, Shuying; Sun, Qianqian; Wu, Qiong; Gui, Wenjun; Zhu, Guonian; Schlenk, Daniel
• Is Part Of: Environmental pollution. Volume 249(2019)
• Page Start: 1049
• Page End: 1059
• Publication Date: 2019-06
• Subjects: Tebuconazole -- Zebrafish -- Endocrine disruption -- Sex differentiation -- Gonadal development; AOP adverse outcome pathway -- BCA bicinchoninic acid -- BCF bioconcentration factor -- BW body weight -- BWe body weight at the end of exposure -- BWi body weight at the initial time of exposure -- CM corrected mortality -- DMSO dimethyl sulfoxide -- dpf days post-fertilization -- DT50 time required to reach 50% disappearance -- DT95 time required to reach 95% disappearance -- ECM embryo-culture medium -- EP egg production -- epf eggs per female -- ESR estrogen receptor -- FC fold of change -- GAPDH glyceraldehyde 3-phosphate dehydrogenase -- GR gender ratio -- GSI gonadal somatic index -- HSI hepatic somatic index -- hpf hours post-fertilization -- HPG hypothalamic-pituitary-gonadal -- HRP horse radish peroxidase -- PVDF polyvinylidene fluoride -- rpm runs per minute -- SR survival rate -- TMS tricaine methanesulfonate -- VC vehicle control -- WBL whole body length -- WBLe whole body length at the end of exposure -- WBLi whole body length at the initial time of exposure; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.03.067
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Tebuconazole is a widely used fungicide that has been detected in water ecosystems, of which the concentrations may affect the endocrine function of aquatic organisms. At present study, tissue-specific bioaccumulation of tebuconazole was found in ovary of adult zebrafish, indicating a potential risk of endocrine disruption. In order to evaluate the potential endocrine disrupting effects, three life stages (2 hpf (hours post-fertilization) −60 dpf (days post-fertilization), Stage I; 60–120 dpf, Stage II; 180–208 dpf, Stage III) of zebrafish ( Danio rerio ) were chronically exposed to tebuconazole at the concentrations ranging from 0.05 mg/L to 1.84 mg/L. Result showed that exposed to tebuconazole could lead to a male-biased sex differentiation in juvenile zebrafish and significant decrease of the percentage of germ cells in sexually-mature zebrafish. Egg production was significantly inhibited by 57.8% and 19.2% after Stage II- and Stage III-exposures, respectively. The contents of 17β-estradiol in gonad decreased by 63.5% when exposed to 0.20 mg/L tebuconazole at Stage II and by 49.5% after exposed to 0.18 mg/L tebuconazole at Stage III, respectively. For all stages exposure, reductions in 17β-estradiol/testosterone ratio were observed, indicating an imbalance in steroids synthesis. Additionally, tebuconazole reduced the expression of cy p19a, which was consistent with the decrease of E2 level. In overall, the present findings indicated that, playing as an anti-estrogen-like chemical, tebuconazole inhibited the expression of Cyp19, thereby impairing steroid hormones biosynthesis, leading to a diminished fecundity of zebrafish. Graphical abstract: Image 1 Highlights: Tebuconazole plays as an anti-estrogen endocrine disrupting effects on zebrafish. Tebuconazole induces a male-biased gonadal differentiation in juvenile zebrafish. Tebuconazole delays development of germ cells in puberty and adult zebrafish. Block of E2 pathway may be the disrupting mechanism caused by tebuconazole. Abstract : Tebuconazole blocks E2 pathway, thereby leading to a male-biased differentiation in juvenile zebrafish and delaying germ cells development in puberty and adult zebrafish, playing an antiestrogen-like role.