Short-chain PFAS exposure alters embryonic development and behavior in zebrafish

Abstract

Per- and polyfluoroalkyl substances (PFAS) are manmade chemicals that are persistent in the environment and have been linked to various physiological and neurobehavioral outcomes, including anxiety disorders. Trifluoroacetic acid (TFA), a short chain PFAS and the most common PFAS degradation product, is increasingly detected in water, soil, and human blood, raising significant concerns about its developmental toxicity. However, the impact of early-life TFA exposure on neurodevelopment and behavior remain insufficiently characterized. In this study, we employed Zebrafish (Danio rerio) embryos as a New Approach Methodology (NAM), to evaluate the development, behavior, and protein expression changes in response to early-life TFA exposure. Embryos were exposed to environmentally relevant low and high concentrations of TFA beginning at one-cell stage. Early developmental physiology was assessed by measuring viability, tail twitch response, hatching rates, and chorion diameters during embryogenesis. Anxiety-like behaviors were evaluated at 5- and 6-days post-fertilization using validated behavioral assays such as the Light-Dark Test and Startle Response. Each test evaluates distinct anxiety-related behaviors by measuring locomotor activity, thigmotaxis (wall preference), and stimulus reactivity, with anxious zebrafish larvae showing increased movement in light and greater wall preference. Then to identify molecular pathways underlying observed developmental phenotypes with TFA exposure, proteomic analyses were performed on embryos at 24- and 48-hours post-fertilization. Our results indicate that TFA exposure altered developmental physiology, evidenced by reduced chorion diameters, and lead to increased anxiety-like behaviors with larvae exhibiting thigmotaxis. These phenotypic changes were accompanied by detectable alterations in the embryonic proteome. Collectively, our findings provide insight into how short-chain PFAS exposure during critical windows of development may contribute to neurobehavioral dysfunction, highlighting potential risks relevant to inform public health policies and environmental regulations.