Evaluating the use of the extracellular flux analyzer assay to determine mitochondrial effects of pesticides with zebrafish (Danio rerio).

Pesticides are used to control pest organisms and diseases in order to protect products and increase productivity. Improper use of these pesticides can lead to environmental accumulation in water, where they can become a risk to non-target organisms. Zebrafish, Danio rerio, are a powerful high-throughput tool in assessing human and ecological health risks of pesticide exposures. In this study, we used the zebrafish model to systematically test organismal and subcellular toxicity of 24 widely used pesticides by quantifying morphological deformities and mitochondrial dysfunction following exposure. We first performed a 96-h developmental assessment to evaluate deformities following exposure to each individual pesticide and used these results to determine sub-teratogenic concentrations to test for mitochondrial toxicity in a 96-well plate-based assay. Developmental deformities at 96 h post-fertilization (hpf) were a reliable indicator of toxicity for almost all pesticides tested in this study. A variety of types of deformities were observed, but compound-specific types of alterations were associated with chlorothalonil, tefluthrin, and pydiflumetofen. Changes in mitochondrial function at 24 hpf included a decrease in ATP-linked respiration following exposure to fludioxonil and butafenacil. Increased ATP-linked respiration and decreased proton leak were observed for profenofos, prosulfocarb, and propiconazole. A non-monotonic dose-response was found for S-metolachlor. Broadly, our results inform aquatic toxicity thresholds for the 24 pesticides tested. Furthermore, the mitochondrial function assay provided a powerful addition to pesticide screening, given the emergence of mitochondrial health as a key indicator of subcellular health related to human disease susceptibility as well as ecological fitness of aquatic organisms.

Duke Scholars

Author Nishad Jayasundara Environmental Natural Science

Author Richard T. Di Giulio Environmental Natural Science