Developmental Neurotoxicity and Behavioral Screening in Larval Zebrafish with a Comparison to Other Published Results

Abstract

With the abundance of chemicals in the environment that could potentially cause neurodevelopmental deficits, there is a need for rapid testing and chemical screening assays. This study evaluated the developmental toxicity and behavioral effects of 61 chemicals in zebrafish (Danio rerio) larvae using a behavioral Light/Dark assay. Larvae (n = 16–24 per concentration) were exposed to each chemical (0.0001–120 μM) during development and locomotor activity was assessed. Approximately half of the chemicals (n = 30) did not show any gross developmental toxicity (i.e., mortality, dysmorphology or non-hatching) at the highest concentration tested. Twelve of the 31 chemicals that did elicit developmental toxicity were toxic at the highest concentration only, and thirteen chemicals were developmentally toxic at concentrations of 10 µM or lower. Eleven chemicals caused behavioral effects; four chemicals (6-aminonicotinamide, cyclophosphamide, paraquat, phenobarbital) altered behavior in the absence of developmental toxicity. In addition to screening a library of chemicals for developmental neurotoxicity, we also compared our findings with previously published results for those chemicals. Our comparison revealed a general lack of standardized reporting of experimental details, and it also helped identify some chemicals that appear to be consistent positives and negatives across multiple laboratories.

Nicotine and Cytisine Embryotoxicity in the Experimental Zebrafish Model

“…After the experiment, the larvae were euthanized by immersion in a 15 µM tricaine methanesulfonate (Sigma Aldrich, St. Louis, MO, USA) solution. Although zebrafish are social animals, and their interactions with other fish can influence their behavior, and physiological response, we may suggest that separate rearing of zebrafish embryos did not affect the results of FET, as it was previously revealed [38]. To address these concerns and minimize bias, we implemented the following strategies: Randomization and appropriate control groups that are raised and treated identically to the experimental groups, except for exposure to the toxic agent, are crucial for establishing a baseline for comparison.…”

New approach methods to assess developmental and adult neurotoxicity for regulatory use: a PARC work package 5 project

“…Relative to in vitro systems, metabolically competent zebrafish embryos may address potential toxicokinetics that can affect toxicity outcomes ( Chu and Sadler, 2009 ). Regarding neurotoxicity, the assessment of neurobehavioral effects caused by xenobiotic exposure is advantageous because these perturbations are sensitive (i.e., they occur at sub-morphological concentrations) ( Noyes et al, 2015 ; Bruni et al, 2016 ; Gaballah et al, 2020 ; Jarema et al, 2022 ). Locomotor activity can function as an automated and generalized readout of neurodevelopment.…”

Zebrafish (Danio rerio) as a Model for the Study of Developmental and Cardiovascular Toxicity of Electronic Cigarettes

“…Both Zebrafish and human studies have reported neurobehavioral effects following e-cigarette exposure. Zebrafish exposed to e-cigarette aerosols altered locomotor activity and anxiety-like behaviors [ 59 , 126 , 132 , 133 , 134 , 135 ], similar to human behavioral changes [ 136 , 137 ].…”