Environmentally relevant concentrations of di(2-ethylhexyl)phthalate exposure alter larval growth and locomotion in medaka fish via multiple pathways
Journal
Science of the Total Environment
Journal Volume
640-641
Pages
512-522
Date Issued
2018
Author(s)
Abstract
Di(2-ethylhexyl)phthalate (DEHP) is a commonly used plasticizer, with evidence of ubiquitous human exposure and widespread occurrence in the aquatic environment. It is an emerging environmental pollutant with regulatory priority; however, most studies have focused on the toxicity of DEHP related to endocrine disruption and reproduction in mammals. The ecotoxicological impact of phthalates (e.g., DEHP) on early life stages of fish under environmentally relevant concentrations of chronic exposure remains unclear. In this study, 7-day post-hatching fry of medaka fish (Oryzias latipes) underwent 21-day continuous exposure to DEHP solutions at 20, 100 and 200 μg/L to assess the effects on fish development and locomotion and related toxic mechanisms. Larval mortality was low with DEHP (20–200 μg/L) within 21 days, but such exposure significantly reduced fish body weight and length and altered swimming behavior. At 21 days, DEHP exposure resulted in specific patterns of larval locomotion (e.g., increased maximum velocity and absolute turn angle) and dose-dependently increased the mRNA expression of acetylcholinesterase (ache) but did not alter AChE activity. Transcriptional expression of antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase and peroxisome proliferation-activated receptor and retinoid X receptor genes was significantly suppressed with 21-day DEHP exposure (20–200 μg/L), with marginal alteration in reactive oxygen species levels and antioxidant activities within the dosing period. As well, DEHP altered the mRNA expression of p53-regulated apoptosis pathways, such as upregulated p53, p21 and bcl-2 and downregulated caspase-3 expression, with increased enzymatic activity of caspase-3 in larvae. Our results suggest that toxic mechanisms of waterborne DEHP altered fish growth and locomotion likely via a combined effect of oxidative stress, neurotoxicity and apoptosis pathways. ? 2018 Elsevier B.V.
Subjects
Apoptosis; Growth inhibition; Medaka fish; Neurotoxicity; Oxidative stress
SDGs
Other Subjects
Antioxidants; Cell death; Enzymes; Esters; Gene expression; Oxidative stress; Peptides; Toxicity; Anti-oxidant activities; Di-2-ethylhexyl phthalate; Early life stages of fishes; Environmental pollutants; Glutathione S-transferases; Growth inhibition; Neurotoxicity; Reactive oxygen species; Fish; acetylcholinesterase; caspase 3; catalase; glutathione peroxidase; glutathione transferase; messenger RNA; peroxisome proliferator activated receptor; phthalic acid bis(2 ethylhexyl) ester; protein bcl 2; protein p21; protein p53; reactive oxygen metabolite; retinoid X receptor; superoxide dismutase; phthalic acid bis(2 ethylhexyl) ester; apoptosis; bioaccumulation; ecological impact; ecotoxicology; enzyme activity; fish; growth response; larval development; locomotion; organic pollutant; oxidative stress; pollution exposure; swimming behavior; acetylcholinesterase gene; animal cell; animal experiment; animal model; animal tissue; apoptosis; Article; bcl 2 gene; body height; body weight; caspase 3 gene; catalase gene; cell cycle arrest; controlled study; down regulation; ecotoxicity; environmental exposure; enzyme activity; gene control; gene expression; glutathione peroxidase gene; glutathione S transferase gene; growth disorder; hatching; health hazard; larval development; locomotion; male; mortality; motor dysfunction; neurotoxicity; nonhuman; Oryzias latipes; oxidative stress; p21 gene; p53 gene; peroxisome proliferator activated receptor gene; priority journal; protein function; retinoid X receptor gene; superoxide dismutase gene; swimming; toxic concentration; upregulation; animal; larva; Oryzias; physiology; reproduction; toxicity; toxicity testing; water pollutant; Mammalia; Oryzias latipes; Oryziinae; Animals; Diethylhexyl Phthalate; Larva; Oryzias; Reproduction; Toxicity Tests; Water Pollutants, Chemical
Type
journal article