Reproductive toxicity and transgenerational effects of co-exposure to polystyrene microplastics and arsenic in zebrafish.

Microplastics (MPs) are ubiquitous environmental pollutants that have garnered significant attention due to their small particle size, resistance to degradation and large specific surface area, which makes it easy to adsorb various pollutants, particularly heavy metals. Arsenic (As), a common metal poisons, poses significant risks due to its widespread industrial use. When MPs and As co-exist in the environment, they can exert combined toxic effects on organisms, affecting various systems, including the nervous system. However, research on the reproductive damage caused by the co-exposure to MPs and As is limited, and the toxic effects and mechanisms remain unclear. In this study, we investigated the co-exposure of polystyrene microplastics (PSMP) and As on female zebrafish to evaluate the reproductive toxicity and transgenerational effects. The results revealed that the combined exposure exhibited elevated reproductive toxicity, resulting in reduced gonadal indices, abnormal oocyte maturation, and disrupted sex hormone levels, as evidenced by an increased E2/T ratio. Metabolomics analyses revealed that the co-exposure to PSMP and As primarily affected pathways involved in aminoacyl-tRNA biosynthesis, sphingolipid metabolism, linoleic acid metabolism, galactose metabolism, and amino sugar and nucleotide sugar metabolism. These pathways are associated with oxidative stress, lipid synthesis, and sex hormone synthesis. Importantly, the combined exposure group exhibited more pronounced effects on offspring development compared to the alone treatment group, characterized by increased mortality rate, decreased hatching rate, and reduced heart rate. These findings provide evidence that co-exposure to MPs and As damages the reproductive system and adversely affects offspring growth and development.