The combined toxicity assessment of polystyrene microplastics and di(2-ethylhexyl) phthalate on cardiac development in zebrafish embryos

With the extensive use of microplastics (MPs) and its plasticizer, more and more research focus on their combined effects on health risk. In this study, polystyrene (PS) and di(2-ethylhexyl) phthalate (DEHP) were selected as target contaminants, and zebrafish embryos were employed as a biological model to investigate the potential toxicity of co-exposure to microplastics and plastic additives on embryonic and cardiac development. These findings indicated that the simultaneous exposure to PS and DEHP markedly diminished the heart rate, survival rate, and impeded the hatching process. The combined exposure group exhibited elevated levels of oxidative stress and an increased number of apoptotic cells. Fluorescence photography of zebrafish embryos revealed an increase in the distance of SV-BA in combined exposure. Transcriptomics analysis revealed a reduction in the expression of yeats4, a gene involved in regulating DNA damage response and cell death. Metabolomics analysis revealed that amino acid metabolism plays a critical role in the toxic effects of combined PS and DEHP exposure on zebrafish larvae, while the Apelin signaling pathway, vascular smooth muscle contraction, and calcium ion signaling pathway may be key pathways involved in the cardiac toxic effects of PS and DEHP co-exposure in zebrafish larvae.