Comparative impact of polystyrene, rice bag-derived high-density polyethylene nanoparticles, and polystyrene–silver nanoparticle interactions in a 28-day in vivo study in male and female Wistar rats

Exposure to plastic nanoparticles (PNPs) has become a significant public health and environmental concern due to their pervasive presence and potential toxic effects. However, the long-term effects of different PNPs types, their interactions with other nanoparticles, and effects across sexes, remain poorly understood. This study aimed to evaluate sex-specific physiological, biochemical, and genotoxic effects of chronic exposure to polystyrene nanoparticles (PS-NPs), silver nanoparticles (AgNPs), high-density polyethylene nanoparticles (HDPE-NPs) isolated from food packaging, and a mixture of PS-NPs and AgNPs in male and female rats. Nanoparticles were administered daily for 28 days via oral gavage, after which selected systemic, metabolic, and genotoxic endpoints were assessed. Despite no overt systemic toxicity or major liver damage, we found changes in cholesterol levels, especially in females, and signs of DNA damage, suggesting potential genotoxicity. The combination of PS-NPs/AgNPs triggered liver stress responses, implying additive or synergistic effects. Importantly, females showed greater sensitivity in terms of lipid metabolism, whereas HDPE-NPs-treated male group reduced testicular weight. These findings underscore the necessity of including both sexes in nanoparticle toxicity studies and highlight the need for a better understanding of the health risks of nanoplastics and their interactions with other co-occurring contaminants under realistic exposure conditions.