Seizurogenic effect of perfluorooctane sulfonate in zebrafish larvae

While the developmental neurotoxicity of perfluorooctane sulfonate (PFOS) has been reported, its seizurogenic potential has not been investigated. Behavior assessment was conducted in zebrafish larvae exposed to PFOS at concentrations of 0, 0.1, 1, 5, 10, and 20 μM. Changes in electrophysiological signals and in the concentration of 20 neurochemicals were measured. Behavior assessment revealed that PFOS altered larval behaviors and significantly increased the counts and duration of bursting (an irregular high-speed movement). Electrophysiological analysis showed that the number of seizure-like events and duration of seizure-like signals were significantly increased, corresponding to results observed using pentylenetetrazol as a positive seizurogenic agent. The outbreak of seizures detected via abnormal electrophysiological signals was confirmed by the increased expression of c-fos and bdnf, which are typical seizure-related genes. Analysis of neurochemicals indicated that PFOS dysregulated overall neurotransmission systems, and aberrant endogenous concentrations of various neurochemicals in the amino acid, cholinergic, dopaminergic, serotonergic and kynurenergic, and GABAergic systems were associated with seizure-like behavior and signals. This study, the first to demonstrate that exposure to PFOS provokes a seizurogenic effect in developing zebrafish larvae, should stimulate further research on the association between PFOS exposure and neurodevelopmental toxicity or neurological disorders.