Acute exposure to DE-71 causes alterations in visual behavior in zebrafish larvae

Area of Science:

• Environmental toxicology
• Neuroscience
• Ophthalmology

Background:

• Polybrominated diphenyl ethers (PBDEs) are known neurotoxicants.
• The specific effects of PBDEs on visual behavior are not well understood.
• Zebrafish larvae are a suitable model for studying developmental toxicity.

Purpose of the Study:

• To investigate the impact of PBDEs on visual behavior in zebrafish larvae.
• To examine the biochemical and structural changes in the eye following PBDE exposure.
• To assess the relationship between PBDE-induced ocular changes and behavioral alterations.

Main Methods:

• Zebrafish embryos were exposed to a PBDE mixture (DE-71) at various concentrations.
• Photoreceptor opsin expression, retinal histology, and visual behaviors (optokinetic response, phototaxis) were assessed.
• Western blotting and histological examinations were used to analyze ocular changes.

Main Results:

• PBDE exposure led to significant upregulation of opsin genes (zfrho, zfgr1) and increased rhodopsin protein.
• Retinal histology showed alterations including increased inner nuclear layer area and decreased inner plexiform layer and ganglion cell density.
• Larvae exhibited hyperactive visual behaviors, including increased saccadic eye movements and phototactic responses.

Conclusions:

• Acute PBDE exposure causes biochemical and structural changes in the zebrafish eye.
• These ocular alterations result in significant changes in visual behavior.
• Visual behavioral paradigms can serve as indicators for the adverse effects of toxicants on visual function.