Toxicogenomic Responses of Zebrafish Embryos/Larvae to Tris(1,3-dichloro-2-propyl) Phosphate (TDCPP) Reveal Possible Molecular Mechanisms of Developmental Toxicity

Abstract

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is frequently present in indoor dust and can be detected in human milk. In order to evaluate the effects of TDCPP on vertebrate development, zebrafish embryos/larvae were used as an animal model to examine developmental phenotypes and explore possible mechanisms of toxicity by employing microarrays and iTRAQ labeling quantitative proteomics. The results demonstrated that treatment with TDCPP (3 μM) from 0.75 h postfertilization (hpf) inhibited cell rearrangement at 4 hpf, caused delay in epiboly at 5.7 and 8.5 hpf, and led to abnormal development (e.g., short tail, reduced body size) and lethality between 14 and 45 hpf, which might be related with altered expression of genes regulating embryogenesis. Furthermore, trunk curvature was observed as the main phenotype in 96 hpf zebrafish larvae exposed to 1 or 3 μM TDCPP, possibly by changing somite formation and expression of proteins related to fast muscle and cartilage development. Collectively, our results suggest that exposure to TDCPP causes developmental toxicity in vertebrates and warrant the need for studies to evaluate the potential health risks of TDCPP to developing human embryos/infants/children, due to its frequent presence in indoor dust and potential for human exposure.

Multiple bio-analytical methods to reveal possible molecular mechanisms of developmental toxicity in zebrafish embryos/larvae exposed to tris(2-butoxyethyl) phosphate

“…The recovery of extraction of TBEP was 84.15%. For the quantification of TBEP in zebrafish larvae, the analysis was conducted according to a previously published protocol for TDCPP (Fu et al, 2013), using a Waters ACQUITY UPLC system equipped with a Waters ACQUITY triple quadrupole mass spectrometer (Waters, Milford, MA, USA). Briefly, zebrafish larvae were freeze-dried, homogenized and ground with diatomaceous earth.…”

“…Quantitative proteomic analysis was conducted according to previously published methods (Fu et al, 2013). Peptide identification was performed using the following parameters: Cys alkylation: MMT(C), ID focus: biological modification, Digestion: trypsin, Database: zebrafish, Search effort: thorough ID, unused protein score >1.3 (>95% confidence).…”

“…Previous studies have demonstrated that several OP esters cause developmental toxicity and endocrine disruption in vivo and in vitro (Crump et al, 2012;Dishaw et al, 2012;Farhat et al, 2013;Fu et al, 2013;Liu et al, 2012bLiu et al, , 2013McGee et al, 2012McGee et al, , 2013Wang et al, 2013). For example, exposure of zebrafish embryos to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) disrupted embryogenesis and caused larval malformation, with median lethal concentrations (LC 50 ) ranging from 3.7 to 7.0 mg/L (Fu et al, 2013;Liu et al, 2013;McGee et al, 2012;Wang et al, 2013).…”

“…For example, exposure of zebrafish embryos to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) disrupted embryogenesis and caused larval malformation, with median lethal concentrations (LC 50 ) ranging from 3.7 to 7.0 mg/L (Fu et al, 2013;Liu et al, 2013;McGee et al, 2012;Wang et al, 2013). In chicken embryos, Farhat et al (2013) reported that injection of TDCPP or tris(1-chloro-2-propyl) phosphate (TCPP) delayed pipping, reduced tarsus length, and changed hormone concentrations and mRNA levels included in xenobiotic metabolism and thyroid hormone pathways.…”

Establishment of a three-step method to evaluate effects of chemicals on development of zebrafish embryo/larvae

“…These data more comprehensively and quantitatively described changes in morphology during development of larvae exposed to chemicals. In this study, it was determined that exposure to 0.1 or 0.2 mg/L TDCIPP significantly altered lengths of more than 50 lines or angles, while studies using the traditional methods of microscopic examination found no significant malformations due to exposure of zebrafish to concentrations of TDCIPP 0.2 mg/L (McGee et al, 2012;Fu et al, 2013). These results suggest that the three-step method developed during this study is more sensitive than previous methods based on more limited observations through the microscope.…”