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ICCVAM Biennial Report 2020-2021

Biennial Progress Report 2020-2021 Interagency Coordinating Committee on the Validation of Alternative Methods

Development of Cellular and Molecular Approaches to Evaluate Effects of Environmental Contaminants and Stressors in Fish

Aquatic exposure to endocrine disruptors, pesticides, and cyanobacteria affects the health of fish in the environment. Most of the affected species are not typically used in the laboratory and their specific responses to such exposure cannot always be inferred from data from laboratory species. During 2020-2021, USGS scientists (DOI) developed and applied methods to evaluate species-specific cellular and molecular responses to environmental contaminants and thermal stress using primary tissue culture and non-lethal biopsy methods. Specifically, this research focused on brook trout, largemouth bass, and smallmouth bass collected from the upper Chesapeake Bay watershed. Methods used included evaluation of gill biopsy tissue and collection of primary hepatocytes and leukocytes from species that inhabit aquatic ecosystems vulnerable to environmental contamination and thermal stress. Analytical approaches included in vitro exposures, image analysis-based flow cytometry, and transcriptional profiling of gill, hepatic, and immune-responsive genes using RNA-seq and nCounter technologies. These approaches are used to investigate specific mechanistic questions in environmentally relevant fishes to minimize the use of vertebrates.