title: Development of a general baseline toxicity QSAR model for the fish embryo acute toxicity test.
abstract: Fish embryos have become a popular model in ecotoxicology and toxicology. The fish embryo acute toxicity test (FET) with the zebrafish embryo was recently adopted by the OECD as technical guideline TG 236 and a large database of concentrations causing 50% lethality (LC50) is available in the literature. Quantitative Structure-Activity Relationships (QSARs) of baseline toxicity (also called narcosis) are helpful to estimate the minimum toxicity of chemicals to be tested and to identify excess toxicity in existing data sets. Here, we analyzed an existing fish embryo toxicity database and established a QSAR for fish embryo LC50using chemicals that were independently classified to act according to the non-specific mode of action of baseline toxicity. The octanol-water partition coefficient Kowis commonly applied to discriminate between non-polar and polar narcotics. Replacing the Kowby the liposome-water partition coefficient Klipwyielded a common QSAR for polar and non-polar baseline toxicants. This developed baseline toxicity QSAR was applied to compare the final mode of action (MOA) assignment of 132 chemicals. Further, we included the analysis of internal lethal concentration (ILC50) and chemical activity (La50) as complementary approaches to evaluate the robustness of the FET baseline toxicity. The analysis of the FET dataset revealed that specifically acting and reactive chemicals converged towards the baseline toxicity QSAR with increasing hydrophobicity. The developed FET baseline toxicity QSAR can be used to identify specifically acting or reactive compounds by determination of the toxic ratio and in combination with appropriate endpoints to infer the MOA for chemicals.
authors: UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoserstr. 15, 04318, Leipzig, Germany; UFZ - Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318, Leipzig, Germany. Electronic address: nils.kluever@ufz.de.
authors: Nils
authors: N
authors: Klüver
authors: UFZ - Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318, Leipzig, Germany.
authors: Carolina
authors: C
authors: Vogs
authors: UFZ - Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318, Leipzig, Germany; RWTH Aachen University, Institute for Environmental Research, Biologie V, Worringerweg 1, 52074, Aachen, Germany.
authors: Rolf
authors: R
authors: Altenburger
authors: UFZ - Helmholtz Centre for Environmental Research, Department of Cell Toxicology, Permoserstr. 15, 04318, Leipzig, Germany; Eberhard Karls University Tübingen, Center for Applied Geosciences, Environmental Toxicology, Hölderlinstr. 12, 72074, Tübingen, Germany.
authors: Beate I
authors: BI
authors: Escher
authors: UFZ - Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318, Leipzig, Germany.
authors: Stefan
authors: S
authors: Scholz
mesh_terms: D000818:Animals; D054750:Ecotoxicology; D015386:Hazardous Substances; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008954:Models, Biological; D015233:Models, Statistical; D008962:Models, Theoretical; D021281:Quantitative Structure-Activity Relationship; D012044:Regression Analysis; D012995:Solubility; D023382:Toxicity Tests, Acute / Q000379:methods*; D015027:Zebrafish / Q000196:embryology*
chemical_list: D015386:Hazardous Substances
keywords: Chemical activity; FET; Internal lethal concentration; Liposome-water partition coefficient; Toxicity baseline QSAR; Zebrafish embryo