From gonads to generations: Mechanistic insights into reproductive disruption by polystyrene nanoplastics and co-contaminants in fish

Nanoplastics (NPs), particularly polystyrene nanoplastics (PS-NPs), are emerging contaminants of growing concern in aquatic ecosystems due to their pervasive presence and potential to impair reproductive health in fish. This review critically synthesizes current findings on how PS-NPs impair reproductive function in fish. Evidence shows that PS-NPs disrupt gonadal structure, alter sex hormone levels, impair gamete development, and deregulate genes along the hypothalamic–pituitary–gonadal (HPG) axis. Multi-omics data reveal interference with lipid metabolism, steroid hormone synthesis, and vitellogenin production, contributing to reduced fertility and developmental abnormalities. When co-exposed with environmental endocrine-disrupting chemicals (EDCs), PS-NPs often amplify toxicity by enhancing chemical uptake and tissue accumulation, resulting in synergistic and sex-specific effects that can span generations. Key mechanisms include hormonal imbalance, oxidative stress, histopathological damage, and epigenetic alterations. However, critical research gaps remain, including limited environmental detection, short exposure durations, and a narrow focus on model species. Future studies should adopt environmentally realistic designs, expand species coverage, and integrate multi-omics tools to assess long-term reproductive risks of PS-NPs in fish. • PS-NPs disrupt gonadal structure, hormone balance, and gamete development • Co-exposure with EDCs synergistically exacerbates reproductive toxicity in fish • PS-NPs enhance EDC bioaccumulation, causing multigenerational developmental defects • Multi-omics reveal effects on lipid metabolism, steroidogenesis and vitellogenesis • Future work should target monitoring, chronic exposure, and species diversity