Bioconcentration and Transfer of the Organophorous Flame Retardant 1,3-Dichloro-2-propyl Phosphate Causes Thyroid Endocrine Disruption and Developmental Neurotoxicity in Zebrafish Larvae

• Published in: Environmental science & technology 2015-04, Vol.49 (8), p.5123-5132
• Main Authors: Wang, Qiangwei, Lai, Nelson Lok-Shun, Wang, Xianfeng, Guo, Yongyong, Lam, Paul Kwan-Sing, Lam, James Chung-Wah, Zhou, Bingsheng
• Format: Article
• Language: English
• Subjects: Acetylcholinesterase - metabolism; Animals; Danio rerio; Embryo, Nonmammalian - drug effects; Endocrine Disruptors - pharmacokinetics; Endocrine Disruptors - toxicity; Female; Fire extinguishers; Fish Proteins - genetics; Fish Proteins - metabolism; Flame Retardants - pharmacokinetics; Flame Retardants - toxicity; Gene Expression Regulation, Developmental; Homeostasis; Larva - drug effects; Larva - growth & development; Larva - metabolism; Male; Neurotoxicity; Neurotoxicity Syndromes - etiology; Neurotransmitter Agents - metabolism; Organic chemicals; Organophosphorus Compounds - pharmacokinetics; Organophosphorus Compounds - toxicity; Reactive Oxygen Species - metabolism; Ribonucleic acid; RNA; Thyroid diseases; Thyroid gland; Thyroid Gland - drug effects; Thyroid Hormones - metabolism; Zebrafish; Zebrafish - embryology; Zebrafish - metabolism
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.5b00558

Organophosphate flame retardants are emerging environmental contaminants, although knowledge of their health risks is limited. Here, thyroid hormone homeostasis and neuronal development was studied in the progeny of adult zebrafish exposed to tris­(1,3-dichloro-2-propyl) phosphate (TDCPP). Adult zebrafish were exposed to TDCPP (0, 4, 20, and 100 μg/L) for 3 months. Increased generation of reactive oxygen species and reduced survival rates was observed in exposed F1 larvae. We also observed a significant decrease in plasma thyroxine and 3,5,3′-triiodothyronine levels in F0 females and F1 eggs/larvae. The mRNA and protein expression of factors associated with neuronal development (e.g., α1-tubulin, myelin basic protein, and synapsin IIa) were significantly downregulated in exposed F1 larvae, as was the level of the neurotransmitters dopamine, serotonin, gamma amino butyric acid, and histamine. Larval locomotion was significantly decreased in exposed fish, but there was no effect on acetylcholinesterase activity. Bioconcentration of TDCPP was observed in F0 fish. TDCPP was also detected in F1 eggs following parental exposure, indicating maternal transfer of this compound. This study uniquely shows that TDCPP can be transferred to the offspring of exposed adults, causing thyroid endocrine disruption and developmental neurotoxicity.