Comparative transcriptional analysis of methylparaben and propylparaben in zebrafish Ceyhun Bereketoglu, Ajay Pradhan ⁎ Biology, The Life Science Center, School of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden HIGHLIGHTS • Methylparaben and propylparaben in- duce mortality in zebrafish. • Methylparaben and propylparaben in- duce developmental abnormality in zebrafish. • Methylparaben and propylparaben alter genes from different signaling path- ways. • Propylparaben is more toxic than methylparaben in zebrafish. GRAPHICAL ABSTRACT abstract article info Article history: Received 20 February 2019 Received in revised form 11 March 2019 Accepted 22 March 2019 Available online 23 March 2019 Editor: Damia Barcelo Parabens are widely used as preservatives in different commercial items including food, cosmetics and pharma- ceuticals, and their wide use has resulted in accumulation in the environment. Parabens have been shown to have negative effects on animals as well as human health. In this study, we carried out a comprehensive study to de- termine the adverse effects associated with propylparaben (PP) and methylparaben (MP) on early developmen- tal stages of zebrafish. Mortality, hatching, developmental abnormalities and gene expression profiles were investigated in embryos exposed to both compounds. The semi-static exposure conditions showed that both MP (≥100 μM) and PP (≥10 μM) are toxic to the embryos in a concentration-dependent manner and lead to de- velopmental abnormality. Malformations such as spinal defects, pericardial edema, and pigmentation defects were observed following both MP and PP treatments. Hatching delay, mortality and developmental abnormality data indicate that PP is more toxic than MP. For gene expression analysis, 1 and 10 μM doses of MP and PP were analyzed. Genes from physiological pathways including stress response, cell cycle and DNA damage, inflamma- tion, fatty acid metabolism and endocrine functions were affected by MP and PP. The gene expression profiles show that parabens cause toxicity by inducing oxidative stress, DNA double-strand breaks, apoptosis as well as by altering fatty acid metabolism. Altered expression of androgen receptor (ar) and estrogen receptor 2 alpha (esr2a) indicates an antiandrogenic and estrogenic activity of parabens in zebrafish. Overall, the present study provides considerable information on the negative effects of MP and PP using physiological endpoints and moti- vates further studies to explore the molecular mechanism of the toxicity associated with parabens. © 2019 Elsevier B.V. All rights reserved. Keywords: Toxicity Gene expression Stress response Development abnormality Science of the Total Environment 671 (2019) 129–139 ⁎ Corresponding author. E-mail address: ajay.pradhan@oru.se (A. Pradhan). https://doi.org/10.1016/j.scitotenv.2019.03.358 0048-9697/© 2019 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv