Transcriptomics and metabolomics reveal functional nanoplastics-induced male reproductive damage and resveratrol...

Polystyrene nanoparticles (PS-NPs) can undergo surface functionalization under environmental conditions, and their accumulation in living organisms may pose a potential reproductive toxicity risk to males, though the underlying mechanisms remain incompletely understood. This study employed integrated transcriptomic and metabolomic analyses to investigate the molecular mechanisms of testicular injury in male ICR mice induced by a 28-day exposure to plain PS-NPs (PS), amino-modified PS-NPs (PS-NH₂), and carboxyl-modified PS-NPs (PS-COOH) (0.08 μm; 50 mg/kg/day), and to evaluate the concurrent protective effects of resveratrol (RES; 100 mg/kg/day). Results showed that PS-NH₂ and PS-COOH caused severe spermatogenic impairment concurrent with blood-testis barrier disruption and inflammation, marked by mislocalization of ZO-1, occludin, and vimentin, and an imbalance between upregulated TNF-α and downregulated IL-10. RES treatment effectively alleviated these alterations. Transcriptomic analysis identified 1633 differentially expressed genes, primarily associated with lipid metabolism, spermatogenesis, and apoptosis. KEGG enrichment indicated significant involvement of the PI3K-AKT signaling pathway. Metabolomic profiling identified 158 differentially expressed metabolites, linked to pathways such as pyrimidine metabolism, bile secretion, and cholesterol metabolism. Integrated multi-omics analysis suggested that different types of PS-NPs affected distinct biological pathways: the PS group was mainly associated with taurine metabolism, the PS-NH₂ group with bile secretion and cholesterol metabolism, and the PS-COOH group with bile secretion and insulin resistance. RT-qPCR analyses confirmed that PS-NPs significantly upregulated the mRNA expression of inflammatory markers (TNF-α, IL-10) and pro-apoptotic factors (BAX, caspase-3), alongside a downregulation of PI3K, AKT, caspase-9, and caspase-8. Increased protein levels of p-AKT, PI3K, the BAX/BCL-2 ratio, and cleaved caspase-3 were observed, concomitant with decreased levels of caspase-3, caspase-9, and caspase-8. These effects were partially ameliorated by RES treatment. Our data indicate that functionalized PS-NPs induce severe testicular damage, potentially via activation of the PI3K-AKT pathway, alongside induced inflammation and apoptosis. Metabolic disturbances such as those in bile secretion may be contributing factors. Importantly, RES treatment effectively mitigates these adverse effects. Collectively, our study elucidates a key mechanism underlying PS-NPs reproductive toxicity and proposes a promising therapeutic intervention with RES.