Silver nanoparticles induce abnormal touch responses by damaging neural circuits in zebrafish embryos

Area of Science:

• Environmental Toxicology
• Developmental Biology
• Neuroscience

Background:

• Silver nanoparticles (AgNPs) are increasingly used in consumer products.
• The impact of AgNPs on fish embryogenesis and molecular mechanisms remains unclear.

Purpose of the Study:

• To investigate the biological effects of AgNPs on fish embryogenesis.
• To elucidate the molecular mechanisms underlying AgNP toxicity in developing fish.

Main Methods:

• Microarray analysis to identify gene expression changes in AgNP-exposed embryos.
• Quantitative PCR (qPCR), whole-mount in situ hybridization (WISH), and transgenic zebrafish models to validate gene expression.
• Assessment of neurogenesis, neurotransmitter, and synaptic transmission genes.

Main Results:

• AgNPs caused abnormal touch responses and neuron membrane potential in fish embryos.
• Down-regulation of neurogenesis, dopaminergic neurotransmitter, synaptic transmission, and motor neuron genes was observed.
• The observed gene expression changes were largely mediated by silver ions (Ag+) released from AgNPs.

Conclusions:

• AgNPs disrupt fish embryogenesis by damaging neural circuit formation, including dopaminergic pathways and motor activity.
• These disruptions lead to abnormal electrical properties and impaired sensory-motor responses.
• The toxicity of AgNPs during embryogenesis is primarily attributed to released Ag+.