Effects of bisphenol A, two synthetic and a natural estrogens on head regeneration of the freshwater planarians, Dugesia japonica

Abstract

Regeneration is a vital physiological process for survival of adult organisms. Bisphenol A (BPA), diethystilbestrol (DES), 17α-ethinylestradiol (EE2), and 17β-estradiol (E2) were examined for their effects on head formation in decapitated freshwater planarians (Dugesia japonica). The median lethal concentration of the test chemicals and the median inhibitory concentration for decapitated planarians and different regenerative endpoints, were determined for 3–7 d of exposure. For planarian head regeneration, the no-observed-effect level of BPA and DES was 0.05 mg L⁻¹ and 1 mg L⁻¹ for EE2 and E2. The effects of BPA, DES, and EE2 on asexual planarian regeneration did not correspond with the order of their estrogenic potencies, suggesting that the effects, at least partially, were due to general toxicity rather than their estrogenicity. In view of the published data on concentrations of xenoestrogens in water bodies versus the nominal levels tested here, this study suggests that the current environmental levels of BPA, DES, EE2, and E2 have no immediate adverse effects on freshwater planarian regeneration.

Keywords:

• Dugesia japonica
• endocrine disruptor
• developmental toxicity
• regeneration

Acknowledgments

The author would like to thank Mr Chih-Wei Hsu for his assistance on planarian regeneration assays and Mr Siang-Heng Wang for his help to photograph planarian regeneration images. The author appreciates two anonymous reviewers for their critical comments and helpful suggestions to improve and clarify this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This study was supported by the National Science Council [grant number NSC 100-2313-B-002-009-MY3].