MP7 Toxicogenomics in Environmental Studies
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(FEN-1117-812890) Gene expression and metabolic profiling in Danio rerio embryos as a strategy for investigating mechanisms of toxicity.

Fenske, M¹, Schaefers, C², Robinson, M¹, Cossins, A³, Maund, S³, ¹ Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire, United Kingdom² Fraunhofer IME, Schmallenberg, Germany³ School of Biological Sciences, University of Liverpool, Liverpool, United Kingdom

ABSTRACT- Regulators and industry need to develop cost-effective and robust test methods to efficiently predict and assess the potential hazard of chemicals to the environment and human health, while reinforcing animal welfare considerations. Ecotoxicology need to develop approaches, which also allow elucidation of mode-of-action (MOA) and integrate the molecular responses to toxicants. Such integrated approaches may greatly improve our understanding of the mechanisms of toxicity. Applying fish embryos in the development of alternative toxicity (screening) tests offers the opportunity to combine an in-vivo approach with an in-vitro scale test system. The zebrafish (Danio rerio) has emerged as the most suitable species in this context. Apart from being an already well established test species in ecotoxicology it has proved to be a powerful vertebrate model in terms of its reproductive and developmental properties as well as being amenable for forward and reverse genetic approaches. Evidence in the literature of good correlations between acute and zebrafish embryo toxicity data for many toxicants corroborate the potential of this test as an alternative to the acute fish toxicity test. In this project we are developing and validating the zebrafish embryo test as a medium to high-throughput toxicity assay which links morphological and developmental effects with molecular responses at the genome and metabolome level. In a pilot study, embryos were exposed to a selection of environmental toxicants of either known or partially known MOAs at two different concentrations each for 48 h post fertilisation. Embryo development and symptomology were assessed, and surviving embryos after 48 h were subjected to gene profiling analysis using a zebrafish genome array (Affymetrix GeneChip®). We found chemical-specific patterns of altered gene expression although these preliminary results need further verification by single gene expression analysis using real-time PCR. For future studies complementary post-genomic approaches (metabolomics, proteomics) will be included in the analysis.

Key words: zebrafish embryos, mode-of-action, gene profiling analysis, metabolomics