Establishment of a behavioral model to study effects of typical chemicals toward zebrafish larvae

A zebrafish behavioral model is prevalent and has potential to be an important component of chemical screening and toxicity evaluations. However, applications of such zebrafish behavioral assays remain limited because of flaws in monitoring procedures and designs and inconsistent test methodology among published studies. In the present study, a behavioral assay method based on zebrafish larvae was established for rapid chemical toxicity evaluation, which included the optimization of test conditions and the development of behavioral parameters, such as accumulated distance, frequency of active state, acceleration and mobility. To validate the reliability and investigate the specificity of the method developed, the behavioral effects were evaluated for a set of 28 chemicals (flame retardants, pesticides, fungicides or heavy metals) typically reported in the environment and showing effects by various modes of action (MOAs). Our results showed that the most suitable container and volume for behavioral tests of zebrafish larvae was 24-well plate containing 8-mm depth of solution, and the most appropriate developmental period for monitoring was at 5 days post-fertilization (dpf). Chemical exposure led to various dose-dependent responses of the behavioral parameters via different MOAs, e.g. estrogenic chemicals caused hyperactivity through neurodevelopment disturbance and neurotoxic chemicals led to hypoactivity through disruption of nerve signal transmission. Our results suggested that the optimized behavior monitioring method have the potential for identification and classification of neurotoxic chemicals.