Comparative study on the neurotoxicity of five bisphenols using zebrafish embryos/larvae models.

Bisphenols (BPs) are known to exert neurotoxic effects, but comparative studies of their neurotoxicity using equivalent concentrations (instead of identical ones) remain limited. This study assessed the neurotoxicity of bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), fluorine-9-bisphenol (BHPF), and bisphenol AF (BPAF) in zebrafish embryos/larvae exposed to concentrations equivalent to 2 % of each BP's LC50. Results showed all five BPs significantly decreased 72 h post-fertilization (hpf) body length and increased 96 hpf mortality but had no notable impacts on hatching rate, heart rate, or eye span. BPs induced the most prominent hyperactivity and anxiety-like behaviors but impacted the locomotor ability. BPF and BHPF also increased spontaneous tail-coiling frequency under normal and high light, respectively. Molecularly, GABAergic (gad1b, slc6a1b, gabbr1b), dopaminergic (slc6a3, drd1b) and cholinergic (slc5a7a, ache) genes were downregulated. Neurodevelopmental genes (gfap, mbpa, syn2a) were suppressed, while oxidative stress-related genes (sod1, sod2) and metabolic gene cyp3a65 were upregulated. Mechanistically, BPs may trigger oxidative stress and metabolic disruption, interfering with GABAergic/ dopaminergic/cholinergic systems to induce neurobehavioral abnormalities. This study confirms equivalent-concentration comparison as a reliable method for toxicity assessment, highlights the varying neurodevelopmental toxicity of BPs, and provides a basis for environmental chemicals risk management.