Effects of nonylphenol ethoxylate exposure on genes expression along HPG axis of adult male zebrafish
JIANG Jin-lin1, LIU Ren-bin1,2, ZHANG Yu-feng2, LIANG Xia1, SHAN Zheng-jun1
1. Key laboratory of Pesticide Environmental Assessment and Pollution Control, Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing 210042, China;
2. College of Environment, Nanjing Technology University, Nanjing 210009, China
In the present study, the semi-static exposure test method was used for elucidating the effects of different concentrations of nonylphenol polyethylene glycol ether (NPEO) on the hypothalamic-pituitary-gonadal axis (HPG axis) of adult male zebrafish (Danio rerio). The results showed that the expressions of GnRH2, GnRHR1, GnRHR2, GnRHR4, FSHβ and LHβ genes in the brain, as well as the expression of LHR gene in the testis of zebrafish were significantly up-regulated under the exposure of NPEO at the experimental concentrations. The expressions of GnRHR and LHR genes were sensitively to the NPEO exposure at relatively low concentrations and the most sensitive biomarkers were the expressions of GnRHR4 and LHR genes, which were significantly induced under the exposure to 0.001mg/L of NPEO. The expression of CYP17 gene was significantly inhibited in the testis of fish exposed to NPEO at 0.1 and 10mg/L NPEO and on the contrary, the expression of CYP19a gene was significantly induced in the 10mg/L of NPEO group. Up-regulation of GnRH gene indicated that the exposure to NPEO could induce the secretion of GnRH in the hypothalamus and stimulate the secretion of GtH in the pituitary of zebrafish in turn. The exposure to NPEO could promote the synthesis of endogenous estrogen in zebrafish by up-regulating the expression of CYP19a gene and inhibit the synthesis of testosterone (T) by down-regulating the expression of CYP17 gene, and therefore disrupt the sexual hormone homeostasis in zebrafish. The increased levels of estrogen in the testis of zebrafish could produce the negative feedback to the pituitary gland and then stimulated the secretion of GtH in the pituitary, suggesting that NPEO at the experimental concentrations (0.001~10mg/L) could affect the feedback regulation of the HPG axis in male adult zebrafish.
Gao D W, Li Z, Guan J X. Seasonal variations in the concentration and removal of nonylphenol ethoxylates from the wastewater of a sewage treatment plant[J]. Journal of Environmental Sciences, 2017,54:217-223.
Wang Z, Yang Y, Sun W, et al. Nonylphenol biodegradation in river sediment and associated shifts in community structures of bacteria and ammonia-oxidizing microorganisms[J]. Ecotoxicology and Environmental Safety, 2014,106:1-5.
[8]
Zhang Q M, Wang F F, Xue C H, et al. Comparative toxicity of nonylphenol, nonylphenol-4-ethoxylate and nonylphenol-10-ethoxylate to wheat seedlings (Triticum aestivum L)[J]. Ecotoxicology and Environmental Safety, 2016,131:7-13.
[9]
Xu J, Li J M, Feng Z, et al. Neurotoxic effects of nonylphenol:a review[J]. Wiener Klinische Wochenschrift, 2013,125:61-70.
[10]
Shao B, Hu J, Yang M, et al. Nonylphenol and nonylphenol ethoxylates in river water, drinking water, and fish tissues in the area of Chongqing, China[J]. Archives of Environmental Contamination and Toxicology. 2005,48:467-473.
[11]
Priac A, Morin-Crini N, Druart C, et al. Alkylphenol and alkylphenol polyethoxylates in water and wastewater:a review of options for their elimination[J]. Arabian Journal of Chemistry, 2017,41:4511-4523.
Cabaton N J, Wadia P R, Rubin B S, et al. Perinatal exposure to environmentally relevant levels of bisphenol A decreases fertility and fecundity in CD-1mice[J]. Environmental Health Perspectives, 2011, 119:547-552.
Jin X W, Wang Y Y, Jin W, et al. Ecological Risk of Nonylphenol in China Surface Waters Based on Reproductive Fitness[J]. Environmental Science & Technology, 2014,48:1256-1262.
Metcalfe C D, Metcalfe T L, Kiparissis Y, et al. Estrogenic potency of chemicals detected in sewage treatment plant effluents as determined by in vivo assays with Japanese medaka (Oryzias latipes)[J]. Environmental Toxicology and Chemistry, 2001,20:297-308.
[19]
Organization for Economic Co-operation and Development. 21-day Fish Assay:A Short-Term Screening for Oestrogenic and Androgenic Activity, and Aromatase Inhibition[S]. OECD guideline 230, Paris, France, 2009.
[20]
Balch G, Metcalfe C. Developmental effects in Japanese medaka (Oryzias latipes) exposed to nonylphenol ethoxylates and their degradation products[J]. Chemosphere, 2006,62:1214-1223.
Jie Hou, Li Li, Ning Wu, et al. Reproduction impairment and endocrine disruption in female zebrafish after long-term exposure to MC-LR:A life cycle assessment[J]. Environmental Pollution, 2016, 208:477-485.
[24]
Okuzawa K, Gen K, Bruysters M, et al. Seasonal variation of the three native gonadotropin-releasing hormone messenger ribonucleic acids levels in the brain of female red seabream[J]. General and Comparative Endocrinology, 2003,130:324-332.
[25]
Ji K, Hong S, Kho Y, et al. Effects of Bisphenol S Exposure on Endocrine Functions and Reproduction of Zebrafish[J]. Environmental Science & Technology, 2013,47:8793-8800.
[26]
Liu X S, Ji K, Jo A, et al. Effects of TDCPP or TPP on gene transcriptions and hormones of HPG axis, and their consequences on reproduction in adult zebrafish (Danio rerio)[J]. Aquatic Toxicology, 2013,134-135:104-111.
[27]
Bogerd J. Ligand-selective determinants in gonadotropin receptors[J]. Molecular and Cellular Endocrinology, 2007,260-262:144-152.
[28]
Ji K, Liu X, Lee S, et al. Effects of non-steroidal anti-inflammatory drugs on hormones and genes of the hypothalamic-pituitary-gonad axis, and reproduction of zebrafish[J].Journal of Hazardous Material, 2013,254:242-251.
[29]
Han X B, Lei E N, Lam M H, et al. A whole life cycle assessment on effects of waterborne PBDEs on gene expression profile along the brain-pituitary-gonad axis and in the liver of zebrafish[J]. Marine Pollution Bulletin, 2011,63:160-165.
[30]
Zhao Y, Xie L, Yan Y. Microcystin-LR impairs zebrafish reproduction by affecting oogenesis and endocrine system[J]. Chemosphere, 2015, 120:115-122.
[31]
Fernandes D, Schnell S, Porte C. Can pharmaceuticals interfere with the synthesis of active androgens in male fish? an in vitro study[J]. Marine Pollution Bulletin, 2011,62:2250-2253.
[32]
Baudiffier D, Hinfray N, Vosges M, et al. A critical role of follicle-stimulating hormone(Fsh) in mediating the effect of clotrimazole on testicular steroidogenesis in adult zebrafish[J]. Toxicology, 2012,298:30-39.
