PUBLICATION

Effects of waterborne exposure to environmentally relevant concentrations of selenite on reproductive function of female zebrafish: A life cycle assessment

Authors
Mo, A., Wang, X., Yuan, Y., Liu, C., Wang, J.
ID
ZDB-PUB-210109-20
Date
2020
Source
Environmental pollution (Barking, Essex : 1987)   270: 116237 (Journal)
Registered Authors
Keywords
HPGL axis, Progeny development, Reproductive maturity, Selenite, Zebrafish
MeSH Terms
  • Animals
  • Female
  • Gonads
  • Life Cycle Stages
  • Reproduction
  • Selenious Acid
  • Vitellogenins
  • Water Pollutants, Chemical*/toxicity
  • Zebrafish*
PubMed
33412467 Full text @ Environ. Pollut.
Abstract
Recently, bioaccumulation of dietary organic selenium (Se) in the ovaries and inhibition of reproduction in female aquatic animals have been reported. However, there is limited data on the subtle reproductive impacts of waterborne exposure to inorganic Se in fish. Here, zebrafish embryos (2 h post-fertilization) were exposed to solutions with environmentally relevant levels of Na2SeO3 with concentrations of 0 (control), 7.98 ± 0.31, 25.14 ± 0.15, and 79.60 ± 0.81 μg Se/L for 120 d until they reached sexual maturity. Female zebrafish were selected for reproductive toxicity assessment. In the early embryonic stage, whole-mount in situ hybridization of zebrafish embryos showed that waterborne Na2SeO3 exposure did not affect the observed location of vasa expression in primordial germ cells at 24, 48, and 72 h post-fertilization. Life-cycle exposure to 25.14 ± 0.15 and 79.60 ± 0.81 μg Se/L Na2SeO3 did not change the testosterone and 17β-estradiol contents in female zebrafish at the endpoint of exposure, but significantly reduced the proportion of early vitellogenic oocytes and mature oocytes. Follicle maturity retardation was accompanied by changes in transcriptional levels of the genes related to the hypothalamus-pituitary-gonad-liver (HPGL) axis. Transcriptional levels of cyp19a and lhr in the ovary were down-regulated, while the transcriptional level of fshr in the ovaries was up-regulated. In the 21-day cumulative spawning experiment, Na2SeO3 (25.14 ± 0.15 and 79.60 ± 0.81 μg Se/L) caused fewer eggs to be produced. Additionally, the malformation of zebrafish offspring significantly increased in the group exposed to 79.60 ± 0.81 μg Se/L. In conclusion, for the first time, this study shows that life-cycle exposure to environmentally relevant concentrations of waterborne Na2SeO3 significantly delays ovarian maturation and reduces the fertility of the female zebrafish.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping