Relative developmental toxicity of short-chain chlorinated paraffins in Zebrafish (Danio rerio) embryos.
Short-chain chlorinated paraffins (SCCPs) are ubiquitous in the environment and might cause adverse environmental and human health effects. Little is known about the relative toxicity of different SCCP compounds especially during development. The objective of this study was to characterize and compare effects of seven SCCP groups at environmentally relevant levels, using a zebrafish (Danio rerio) model. Observations on malformation, survival rates at 96 h post fertilization (hpf), and hatching rates at 72 hpf indicated that the C10-groups (C10H18Cl4, 1,2,5,6,9,10-C10H16Cl6and C10H15Cl7) were more toxic than the C12-groups (C12H22Cl4, C12H19Cl7and 1,1,1,3,10,12,12,12-C12H18Cl8) and Cereclor 63L. The C10-groups were also more potent than C12-groups and Cereclor 63L in decreasing thyroid hormone levels. Among the three compounds within the C10-group, the compounds with less chlorine content had stronger effects on sub-lethal malformations but less effects on triiodothyronine (T3) and tetraiodothyronine (T4). Only C10H18Cl4significantly decreased the mRNA expression of tyr, ttr, dio2 and dio3 at a dose-dependent manner suggesting that the specific mode of actions differ with different congeners. The mechanisms of disruption of thyroid status by different SCCPs could be different. C10H18Cl4might inhibit T3 production through the inhibition effect on dio2. These results indicate that SCCP exposure could alter gene expression in the hypothalamic-pituitary-thyroid (HPT) axis and thyroid hormone levels. The mechanisms of disruption of thyroid status by different SCCPs could be different. Our results on the relative developmental toxicities of SCCPs will be useful to reach a better understanding of SCCP toxicity supporting environmental risk evaluation and regulation and used as a guidance for environmental monitoring of SCCPs in the future.
International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (HIT), Harbin, 150090, China; Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
Lihua
L
Liu
International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (HIT), Harbin, 150090, China. Electronic address: ijrc_pts_paper@yahoo.com.
Yifan
Y
Li
Research Center for Brewing and Food Quality, Technische Universität München, Alte Akademie, 3D-85354, Freising, Germany.
Mehmet
M
Coelhan
Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada. Electronic address: laurie.chan@uottawa.ca.
Hing Man
HM
Chan
International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (HIT), Harbin, 150090, China.
Wanli
W
Ma
International Joint Research Centre for Persistent Toxic Substances (IJRC-PTS), State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (HIT), Harbin, 150090, China.
Liyan
L
Liu
D000818:Animals; D002713:Chlorine / Q000633:toxicity; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000633:toxicity*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D010232:Paraffin / Q000633:toxicity*; D013961:Thyroid Gland / Q000187:drug effects* / Q000378:metabolism; D013963:Thyroid Hormones / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish / Q000254:growth & development* / Q000378:metabolism
C485044:Cereclor; D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D013963:Thyroid Hormones; D002713:Chlorine; D010232:Paraffin
Developmental toxicity; Short-chain chlorinated paraffins (SCCPs); Thyroid hormone; Zebrafish (Danio rerio)