Amitraz exposure induces neurobehavioral toxicity in zebrafish associated with cerebrovascular and BBB-related alterations.

Amitraz (AMT) is a formamidine acaricide widely used in agriculture. The incidence of AMT poisoning shows an increasing trend, yet its neurotoxic effects on non-target organisms remain poorly understood. In this study, zebrafish embryos were used to investigate the developmental and neurobehavioral toxicity of AMT and the underlying mechanisms. Embryos were exposed to varying concentrations of AMT (1, 2.5, and 5 μM) from 4 to 120 h post-fertilization. The results showed that AMT concentration-dependently inhibited embryonic development. Behavioral analyses revealed significant impairments in locomotor activity, including decreased swimming distance and velocity. Mechanistically, AMT exposure was associated with cerebrovascular abnormalities, including vascular disruption and hemorrhage, as well as brain apoptosis, accompanied by oxidative stress and inflammation. Additionally, AMT disrupted energy metabolism and altered multiple neurotransmitter systems, including GABAergic, glutamatergic, and cholinergic pathways. Transcriptomic analysis further confirmed that AMT altered expression of genes involved in oxidative stress, apoptosis, inflammation, cerebrovascular development, BBB-related processes, neurodevelopment and synaptic function. Taken together, AMT triggers developmental toxicity and neurobehavioral deficits in zebrafish, which are associated with cerebrovascular/BBB-related alterations, oxidative stress, impaired neuronal development, and neurotransmitter imbalance. These findings provides insights into the mechanisms underlying AMT-induced neurodevelopmental toxicity in aquatic organisms.