Study on the neurotoxicity of single and combined exposure of phthalate esters and lead to zebrafish brain tissue

In this study, zebrafish (Danio rerio) were employed as a model organism to systematically investigate the individual and combined neurotoxic effects and underlying mechanisms of di-n-octyl phthalate (DNOP), di(2-ethylhexyl) phthalate (DEHP), and lead (Pb) across a range of concentrations, encompassing environmentally relevant levels and higher exposures. The results indicated that individual exposure to DEHP induced significantly greater oxidative stress and neurotransmitter system disruption in zebrafish brain tissue compared to DNOP. Notably, in co-exposure scenarios, the studied phthalic acid esters and Pb primarily exhibited antagonistic interactions. Both individual and combined exposures to these contaminants exacerbated the dysregulation of neurotransmitters, specifically acetylcholine esterase and gamma-aminobutyric acid (GABA), by modulating the gene expression of acetylcholinesterase, GABA A receptor subunit alpha 1, GABA transaminase, and glutamic acid decarboxylase 1 b. This ultimately led to neurotoxicity in the organisms. This research provides a fundamental basis for aquatic ecological risk assessment, human health risk assessment, and pollution management strategies, particularly by elucidating potential effects under elevated environmental burdens and contributing to a broader understanding of dose-response relationships.