Use of an avian hepatocyte assay and the avian toxchip polymerse chain reaction array for testing prioritization of 16 organic flame retardants

• Published in: Environmental toxicology and chemistry 2014-03, Vol.33 (3), p.573-582
• Main Authors: Porter, Emily, Crump, Doug, Egloff, Caroline, Chiu, Suzanne, Kennedy, Sean W
• Format: Article
• Language: English
• Subjects: adverse effects; Animal, plant and microbial ecology; Animals; Applied ecology; Arrays; Avian toxicity; Biological and medical sciences; Biological Assay - methods; Cell Survival; Chain reactions; Charadriiformes; Chemical contaminants; Chemicals; Chickens; Contaminants; Cytotoxicity; Ecotoxicology, biological effects of pollution; eggs; Embryo, Nonmammalian - cytology; Flame retardants; Flame Retardants - toxicity; Fundamental and applied biological sciences. Psychology; Gene expression; General aspects; genes; hepatocytes; Hepatocytes - cytology; Hepatocytes - drug effects; Hepatocytes - metabolism; High-throughput screening; Hormones; In vitro toxicology; Larus argentatus; lethal concentration 50; lipid metabolism; messenger RNA; Phosphates; pollution; Polymerase Chain Reaction - methods; prioritization; Risk assessment; risk assessors; RNA, Messenger - metabolism; Screening; species differences; Species Specificity; TCP (protocol); Thyroid; thyroid hormones; Toxicity; Transcriptome; Transcriptomics
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1002/etc.2469

Risk assessors are challenged with the task of providing data for an increasing number of priority chemicals. High‐throughput toxicity screening methods—which permit rapid determination of toxic, molecular, and/or biochemical effects of a wide range of chemicals—are essential to help meet this demand. The avian embryonic hepatocyte in vitro screening method has been utilized in the authors' laboratory to assess the effects of a wide range of environmental contaminants on cytotoxicity and mRNA expression of genes associated with xenobiotic metabolism, the thyroid hormone pathway, lipid metabolism, and growth. Sixteen structurally variable organic flame retardants (OFRs)—including tetrabromoethylcyclohexane (TBECH), tris(2‐butoxyethyl) phosphate (TBEP), tricresyl phosphate (TCP), and tris(1,3‐dichloro‐2‐propyl) phosphate (TDCPP)—were screened using the in vitro method in the present study. Hepatocytes from 2 avian species, chicken and herring gull, were prepared, and species differences in hepatocyte viability were observed for several OFRs. For example, TCP was not cytotoxic in chicken hepatocytes up to the highest concentration tested (300 µM), whereas the median lethal concentration (LC50) was 31.2 µM in herring gull hepatocytes. Effects on mRNA expression in chicken embryonic hepatocytes were determined using a 3 × 32 custom‐made Avian ToxChip polymerse chain reaction array and were variable among OFRs; TCP, TDCPP, and tris(2,3‐dibromopropyl) isocyanurate showed the most significant alterations among the target genes assessed. Overall, this rapid screening method helped prioritize OFRs for further assessment. For example, OFRs that elicited significant effects on cytoxicity or mRNA expression represent prime candidates for egg injection studies that determine adverse effects on the whole animal but are more costly in terms of time, money, and embryo utilization. Environ Toxicol Chem 2014;33:573–582. © 2013 SETAC