Neural System Impairment and Involved Microglia-Neuron Regulation of Broflanilide in Zebrafish Larvae

Area of Science:

• Environmental toxicology
• Neuroscience
• Ecotoxicology

Background:

• Broflanilide is a widely used insecticide with known aquatic toxicity.
• Previous research indicated central nervous system (CNS) effects at lethal doses.
• Neural impacts and mechanisms at environmentally relevant concentrations remain unclear.

Purpose of the Study:

• To investigate the neurotoxic effects of broflanilide on zebrafish larvae at environmentally relevant concentrations.
• To elucidate the underlying mechanisms of broflanilide-induced neurotoxicity.
• To assess the impact on CNS development, neurotransmission, and neuroinflammation.

Main Methods:

• Zebrafish larvae were exposed to broflanilide (16.9 and 88.0 μg/L) for 120 hours.
• Locomotion, neurotransmitter levels, and neuroanatomy were assessed.
• Gene transcription, microglia activation, and inflammatory markers were analyzed.

Main Results:

• Significant locomotion impairment observed at 88.0 μg/L, with reduced neurotransmitter levels.
• Neuroimaging revealed damage to axons, myelin sheaths, and neurons, with reduced neuron count and altered morphology.
• Broflanilide exposure increased microglia activation, inflammatory cytokines, and neutrophils, indicating neuroinflammation and immune toxicity.
• Abnormal gene transcription related to CNS development was observed.

Conclusions:

• Broflanilide induces neurodevelopmental disorders in zebrafish larvae at environmentally relevant concentrations.
• Neurotoxicity is mediated by interference with microglia-neuron regulation and induction of inflammatory responses.
• Findings highlight the risks of broflanilide to aquatic nervous systems.