Toxic effects of dechlorane plus on the common carp (Cyprinus carpio) embryonic development

Baohua Li,Jianjun Chen,Qiyan Du,Beibei Wang,Ying Qu,Zhongjie Chang

doi:10.1016/j.chemosphere.2020.126481

Abstract

Dechlorane Plus (DP) is a widely used chlorinated flame retardant, which has been extensively detected in the environment. Although DP content in the surface water is low, it can pose a continuous exposure risk to aquatic organisms due to its strong bioaccumulation. Considering that the related studies on the toxicity mechanism of DP exposure are limited, the effect of DP on carp embryo development was evaluated. In the present work, carp embryos were exposed to different concentrations (0, 30, 60, and 120 μg/L) of DP at 3 h post-fertilization (hpf). The expression levels of neural and skeletal development-associated genes, such as sox2, sox19a, Mef2c and BMP4, were detected with quantitative PCR, and the changes in different developmental toxicity endpoints were observed. Our results demonstrated that the expression levels of sox2, sox19a, Mef2c and BMP4 were significantly altered and several developmental abnormalities were found in DP-exposed carp embryos, such as DNA damage, increased mortality rate, delayed hatching time, reduced hatching rate, decreased body length, and increased morphological deformities. In addition, the activities of reactive oxygen species and malondialdehyde were remarkably higher in 60 and 120 μg/L DP exposure groups than in control group. These results suggest that DP can exhibit a unique modes of action, which lead to aberration occurrence in the early development stage of common carps, which may be related to some gene damage and oxidative stress. Besides, the parameters evaluated here can be used as tools to access the environmental risk for biota and humans exposed to DP.

Highlights

Dechlorane Plus (DP) is a polychlorinated flame retardant designed to replace Brominated flame retardants or Mirex (Ji et al, 2018 ), and it is widely used in plastic roofing materials, electrical wires, hard disk connectors of computers, and other polymeric systems (Ren et al 2008)
Our results demonstrated that the expression of sox2, sox19a, Mef2c, and BMP4 were significantly changed and several developmental defects were observed in the exposed carps embryo, such as DNA damage, increased mortality rate, delayed hatching time, decreased hatching rate, decreased body length, increased morphological deformities
The embryo hatching rate in the 120 μg/L treatment groups was consistent at 72 hpf and 48 hpf, indicating the delay in the hatching process is attribute to DP toxicity

Summary

Introduction

Dechlorane Plus (DP) is a polychlorinated flame retardant designed to replace Brominated flame retardants or Mirex (Ji et al, 2018 ), and it is widely used in plastic roofing materials, electrical wires, hard disk connectors of computers, and other polymeric systems (Ren et al 2008). DP is found common in the aquatic environment (Li et al 2014; Sun et al 2017; Tao et al 2015; Wu et al 2016), with a half-life of about 24 years in the water environment It is a typical persistent organic pollutant and has an effect of bio-enrichment and bio-fortification in the biota (OxyChem 2007; Yu et al 2013). Orally feed DP can cause metabolic disorders, signal transduction alteration, and liver oxidative damage in rats (Wu et al 2013). DP can induce DNA damage in Tetrahymena thermophila and marine bivalves ((Dou et al 2015; Baron et al 2016)

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