Reproductive effects of oestrogenic endocrine disrupting chemicals in Astyanax rivularis inhabiting headwaters of the Velhas River, Brazil
SCIENCE OF THE TOTAL ENVIRONMENT
Authors: Weber, Andre Alberto; Moreira, Davidson Peruci; Costa Melo, Rafael Magno; Cruz Vieira, Augusto Bicalho; Prado, Paula Suzanna; Neres da Silva, Mirra Angelina; Bazzoli, Nilo; Rizzo, Elizete
Abstract
The Velhas River is themost polluted river in the state of Minas Gerais, south- eastern Brazil. Due to its historical and environmental relevance, the aim of this study was to evaluate the effects of oestrogenic endocrine disruptors on the reproduction of the lambari Astyanax rivularis, a small- sized species found in headwaters of the Sao Francisco River basin. Quarterly field samplings were carried out during a reproductive cycle in three streams of the upper Velhas River: S1 (reference site) and S2 and S3 (sites contaminated by untreated sewage). Themain oestrogenic compoundswere evaluated in water using HPLC/MS. Molecular, histological and reproductive biomarkerswere assessed in liver and gonad. The results showed higher average concentrations of oestradiol (> 200 ng/l) in S2 and S3, oestrone (> 250 ng/l) in S2 aswell as oestriol (> 200 ng/l), bisphenol A (> 190 ng/l), and nonylphenol (>600 ng/l) in S3 compared to S1 (<70 ng/l for all compounds). In S2 and S3, there was an increase in the proportion of females, higher ELISA levels of vitellogenin (Vtg) and proteins of the zona radiata (Zrp) in liver males. Insulin- like growth factor (IGF- I) levels were lower in S2 males, which also had a smaller body size, a smaller seminiferous tubule diameter, a higher proportion of spermatogonia, and lower proportion of spermatozoa in relation to S1. Histopathological analyses detected an increase in yolk deficient oocytes and over- ripening in the contaminated sites, and these alterationswere associated to a reduction of hepatic Vtg levels and a delay in spawning, respectively. Intersex specimens with perinucleolar follicles in amultifocal distribution in the testis were detected in S2 and S3. These results indicate that chronic exposure to oestrogenic compounds induced endocrine disruption that may affect wild populations of A. rivularis in the Velhas River. (C) 2017 Elsevier B.V. All rights reserved.
DISRUPTION OF HYPOTHALAMUS-PITUITARY-LIVER-GONADS AXIS IN THE ENDANGERED Girardinichthys viviparus EXPOSED TO ENVIRONMENTALLY RELEVANT CONCENTRATIONS OF A MIXTURE OF METALS AND WITH 17 alpha-ETHYNIL ESTRADIOL
REVISTA INTERNACIONAL DE CONTAMINACION AMBIENTAL
Authors: Olivares-Rubio, Hugo F.; Dzul-Caamal, Ricardo; Najera-Martinez, Minerva; Vega-Lopez, Armando
Abstract
Girardinichthys viviparus is an endemic and endangered Mexican fish species with matrotrophic viviparity that only inhabits in some polluted water bodies in the Valley of Mexico. In the current study, G. viviparus of both sexes were exposed for 21 days to a mixture of metals with relevant environmental concentrations (T1) and to the same mixture spiked with 25 ng of 17 alpha-ethynil estradiol (EE2)/L (T2). Some biomarkers involved in endocrine disruption of the hypothalamus-pituitary-liver-gonads axis such as gonadotropins I and II (GtH I and GtH II, respectively), and estradiol (E-2) concentrations in the head and gonads were measured. Vitellogenin (VTG) in the liver and gonads, and metallothionein (MT) in the head, liver and gonads were assessed. Increases of GtH I and decreases in GtH II, and alterations of E2 in the head and gonads were found in fish treated with T1 and T2. Higher content of hepatic and gonadal VTG only in fish treated with T2 was detected. MT was notably induced by T2; however, a time-dependent MT reduction was observed. In both treatments, the hypothalamic-pituitary control point was most affected and their alterations were documented by gonadal and head content of E-2. In female fish, it is most likely that endogenous levels of E-2 diminished the alterations elicited by EE2 on this control point of the axis in contrast with male fish. The endocrine disruption of this fish species is a dynamic and complex process.