Hepatic toxicological and multi-omics alterations associated with short- and long-term nonylphenol exposure in mice

Nonylphenol (NP) is an alkylphenol environmental contaminant with endocrine-disrupting activity and potential hepatotoxicity. However, the molecular responses associated with different NP exposure durations remain insufficiently characterized. In this study, male Kunming mice were exposed to NP through drinking water at 500 μg/L for 10 days (NP-S) or 90 days (NP-L) (n = 8/group), and hepatic toxicological alterations were evaluated using biochemical, histopathological, transcriptomic, metabolomic, and integrative analyses. Network toxicology analysis was first applied as a hypothesis-generating approach to identify candidate NP-associated hepatotoxicity targets. Most candidate targets had corresponding mouse orthologs. Compared with control mice, short-term NP exposure induced substantial transcriptional and metabolic alterations without significant changes in serum aminotransferases, oxidative stress markers, or liver histopathology. In contrast, long-term NP exposure was associated with increased ALT and AST activities, reduced SOD and GSH-Px activities, increased MDA levels, elevated IL-6 and IL-1β levels, and histopathological liver injury. Multi-omics analysis revealed that NP exposure affected pathways related to xenobiotic metabolism, glutathione metabolism, retinol metabolism, lipid remodeling, arachidonic acid metabolism, and inflammatory signaling. WGCNA identified exposure-associated co-expression modules, including an NP-L-associated module correlated with liver injury-related phenotypes. Targeted transcriptomic analysis further indicated coordinated alterations in estrogen receptor/nuclear receptor-related genes, CYP-mediated phase I metabolism, and GST/UGT-mediated phase II detoxification. Integrated transcriptome-metabolome analysis suggested coordinated remodeling of xenobiotic metabolism, oxidative stress, lipid metabolism, and inflammatory responses. Overall, under the present single-dose mouse exposure design, short- and long-term NP exposure were associated with distinct hepatic molecular and toxicological profiles. These findings suggest that early molecular reprogramming may precede overt hepatic injury, whereas prolonged exposure is associated with broader metabolic disturbance and more evident liver toxicity.