Febriyansyah Saputra^1,2 , Chia-Hung Yen¹ , Chi-Ying Hsieh³ , Tsung-Yin Ou⁴ , Yenny Risjani² , Wee-Keat Cheah⁵ , Shao-Yang Hu¹

1 Department of Biological Science and Technology, National Pingtung University of Science and Technology, Pingtung, Taiwan
2 Department of Aquaculture, Faculty of Fisheries and Marine Science, University of Brawijaya, Indonesia
3 Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan
4 Department of Industrial Engineering and Management, National Quemoy University, Kinmen, Taiwan
5 School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia Engineering Campus, 14300 Nibong Tebal, Penang, Malaysia
Author    Correspondence author
International Journal of Marine Science, 2016, Vol. 6, No. 4   doi: 10.5376/ijms.2016.06.0004
Received: 17 Sep., 2015    Accepted: 22 Oct., 2015    Published: 21 Jan., 2016

 Saputra F., Yen C.H., Hsieh C.Y., Ou T.Y., Risjani Y., Cheah W.K., and Hu S.Y., 2016, Toxicity effects of the environmental hormone 4-tert-octylphenol in zebrafish (Danio rerio), International Journal of Marine Science, 6(4):1-12

4-tert-octylphenol (4-t-OP), an environmental exogenous estrogen is produced by microbial degradation of alkylphenol polyethoxylates (APEOs). Although it is well known that 4-t-OP can cause the feminization of male, sterility and deficiency of gonad development of aquatic animals by disrupting the endocrine reproductive signaling, less is known about the effects of 4-t-OP on embryonic development. Moreover, the presence of 4-t-OP were detected in umbilical cord blood samples of newborns suggesting infants during development may expose to the risk of 4-t-OP contaminant, hence to investigate the effect of 4-t-OP on physiological function during embryonic development is necessary. In the present study, zebrafish embryos exposed to 4-t-OP were used to evaluate the toxicity of 4-t-OP. The 50% lethal dose (LD50) for wild type zebrafish embryos exposure to 4-t-OP for 3 days is approximately 1.0 mM, and a high ratio of cardiovascular defects were showed in survival embryos. To observe the cardiovascular defects more efficiently, Tg(fil-1:EGFP) zebrafish embryos was used in 4-t-OP exposure treatment. Following exposure Tg(fil-1:EGFP) zebrafish embryos to 4-t-OP at 1.0 mM for 4 days, a highly proportion of defects revealed in cardiovascular system, including pericardical edema, irregular shape or incomplete looping of ventricle and atrium, the absence of intersegmental vessel in the tail of notochord, unformed parachordal vessel and kinks in the caudal vein. The phenotype of cardiovascular defects was accompanied by reduced heart rate and impaired blood circulation. The mRNA expression levels of transcription factors, which are critical for zebrafish heart chamber formation and blood vessel development, were analyzed by RT-PCR. The results showed that the presence of 4-t-OP significantly induce expression level of ERα and ERβ2, and caused cardiovascular defects by suppressing transcription factor Nkx2.7, Hand2, Tbx2a, Tbx2b, Tbx5a, FGF1a, GATA-4, -5 and -6 in zebrafish. The present study suggests that 4-t-OP affects the cardiovascular development in zebrafish and elucidated that early life exposure to 4-t-OP potentially may take a risk of impaired cardiovascular function.

4-tert-octylphenol;Toxicity;Zebrafish;Cardiovascular development