Developmental Phenotypic and Transcriptomic Effects of Exposure to Nanomolar Levels of 4-Nonylphenol, Triclosan, and Triclocarban in Zebrafish (Danio rerio).

Jessica Phillips,Bridget B Baker,Chia-Chen Wu,Danielle N Meyer,Alex S Haimbaugh,David K Pitts,Jeremiah N Shields,Camille Akemann,Tracie R Baker,Zoha Siddiqua

doi:10.3390/toxics10020053

Jessica Phillips, Bridget B Baker + Show 8 more

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https://doi.org/10.3390/toxics10020053

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Abstract

Triclosan, triclocarban and 4-nonylphenol are all chemicals of emerging concern found in a wide variety of consumer products that have exhibited a wide range of endocrine-disrupting effects and are present in increasing amounts in groundwater worldwide. Results of the present study indicate that exposure to these chemicals at critical developmental periods, whether long-term or short-term in duration, leads to significant mortality, morphologic, behavioral and transcriptomic effects in zebrafish (Danio rerio). These effects range from total mortality with either long- or short-term exposure at 100 and 1000 nM of triclosan, to abnormalities in uninflated swim bladder seen with long-term exposure to triclocarban and short-term exposure to 4-nonylphenol, and cardiac edema seen with short-term 4-nonylphenol exposure. Additionally, a significant number of genes involved in neurological and cardiovascular development were differentially expressed after the exposures, as well as lipid metabolism genes and metabolic pathways after exposure to each chemical. Such changes in behavior, gene expression, and pathway abnormalities caused by these three known endocrine disruptors have the potential to impact not only the local ecosystem, but human health as well.

Highlights

Since the Industrial Revolution, humans have created and used chemicals as a part of technological advancements necessary to meet the demands of the world’s exponentially growing population
Our results show a wide range of responses to these three endocrine disrupting chemicals (EDCs), with notable differences in mortality, morphology, neurobehavior, and gene expression between triclocarban and triclosan, despite their relatively similar functions and chemical structures
Triclocarban led to more significant morphological abnormalities in the 120 h exposure group, whereas none were found with triclosan exposure, but this was likely due to the 100% mortality rate seen at the two highest exposure concentrations (100 and 1000 nM) during both 120 and 24 h exposure periods (Figures 1 and 2)

Summary

Introduction

Since the Industrial Revolution, humans have created and used chemicals as a part of technological advancements necessary to meet the demands of the world’s exponentially growing population. Triclosan and triclocarban are antimicrobial agents banned in soaps in the United States due to evidence that they do not prevent disease or improve health but are toxic and carcinogenic, mainly via endocrine disruption [2]. They are still found in personal care products such as lotions, deodorants, and toothpaste, such as Colgate, which contains 10 mM of triclosan, enter the environment mainly through wastewater effluent [3,4] where they accumulate due to their resistance to biodegradation, with an approximate average of 200 ng/L found for both in U.S surface waters [5]. Triclocarban exposure disrupts thyroid hormones in human cell lines and frogs [12], increases androgenic activity in human cell lines [13], reduces female plasma vitellogenin and estradiol in female fathead minnows, resulting in approximately half the cumulative egg production compared to unexposed fish, and decreases testosterone while increasing estradiol in male fathead minnows at environmentally relevant levels [14]

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