Impact of bisphenol-A on early embryonic development and reproductive maturation
Bisphenol-A (BPA) is a synthetic estrogen and monomer component of polycarbonate plastics and epoxy resins that are widely used in the production of food and beverage containers. It leaches into our food and drink at concentrations shown to have biological consequences. Here we show that exposure to low levels of BPA accelerated early embryonic development within 24 h of exposure, attenuated body growth, and advanced the times of hatching and reproductive maturation in medaka fish (Oryzias latipes). The acceleration in embryonic development and time to hatch were blocked by the thyroid-hormone receptor (TH-R) antagonist amiodarone, suggesting that BPA alters global developmental timing through a thyroid-hormone pathway. Our results are likely to have broad implications regarding the effects of plastic-derived contaminants on embryonic and reproductive development.
Siddharth Ramakrishnan, Nancy L. Wayne, Impact of bisphenol-A on early embryonic development and reproductive maturation, Reproductive Toxicology, Volume 25, Issue 2, February 2008, Pages 177-183, ISSN 0890-6238, 10.1016/j.reprotox.2007.11.002. (http://www.sciencedirect.com/science/article/pii/S0890623807002961) Keywords: Bisphenol-A; Embryo development; Endocrine disruptor; Medaka; Reproduction; Thyroid-hormone
Fig. 1. Representative eye development in vehicle treated embryos (Control) versus those exposed to 200 μg/l BPA on 1 dpf (A) and 2 dpf (B). Magnification 160×. Non-linear contrast enhancement (Adobe Photoshop) was applied uniformly to all four images in (A) and (B). Mean eye development of the entire data set in Control versus 200 μg/l BPA-treated embryos as measured by (C) optic groove intensity at 1 dpf and (D) mean eye density on 2 dpf (A.U. refers to arbitrary units). Asterisks indicate statistically significant differences between BPA and Control fish (P < 0.05).
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Fig. 2. Effects of 200 μg/l BPA on embryonic development and hatching. Data represented as % Control (mean ± S.E.M.). Asterisks indicate statistically significant differences between BPA-treated embryos and controls (95% C.I.).
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Fig. 3. Effect of 200 μg/l BPA on the growth of hatched fish. Body length of fish was used as a measure of growth every 5 days from days 10–30 post-hatching. Error bars for days 10–25 are contained within the symbols on the graph. Asterisks indicate statistically significant differences between BPA and Control fish (repeated measures of analysis of variance, P < 0.01; followed by post hoc Bonferroni multiple comparisons test; at least P < 0.05).
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Fig. 4. Effects of 200 μg/l BPA on (A) sexual maturation and (B) gonadosomatic index. Asterisk represents statistically significant differences between BPA-treated and control (Ctrl) animals (P < 0.005).
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Fig. 5. Dose response analysis of BPA on early embryonic development and hatching. Data represented as % Control (mean ± S.E.M.). Asterisks indicate statistically significant differences between BPA and vehicle treated controls, (95% C.I.). Data from 200 μg/l treatment is repeated from Fig. 2, but was collected at the same time as the lower two doses.
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