Unveiling the Molecular Mechanism of 6PPD and 6PPD-Q in Lipid-Metabolism-Related Diseases Through Network Toxicology and Experimental Validation.

6PPD and its ozonation product 6PPD-quinone (6PPD-Q) are ubiquitous tire-derived pollutants linked to environmental and potential human health risks. This study systematically investigated their mechanisms in lipid-metabolism-related diseases (atherosclerosis, type 2 diabetes, and nonalcoholic fatty liver disease) through network toxicology, transcriptomic validation, molecular docking, and experimental models. Targets of 6PPD and 6PPD-Q were predicted using multiple databases and intersected with disease-associated genes. Protein-protein interaction networks, hub gene screening, GO/KEGG enrichment, and GEO transcriptomic datasets identified key shared core targets, including PTGS2, MMP9, CXCL8 (for 6PPD), MAPK14, and PTGS2 (for 6PPD-Q). Molecular docking suggested potential strong binding affinities. Integrative analysis highlighted convergence on oxidative stress, inflammation, lipid dysregulation, and MAPK signaling. In vivo, 40-day exposure to 6PPD and 6PPD-Q in C57BL/6 mice induced hepatic steatosis, elevated serum TC, LDL-C, and HDL-C, upregulated inflammatory cytokines (TNF-α, IL1B, IL6, and IFNG), and core targets. In vitro, both compounds caused dose-dependent cytotoxicity, ROS accumulation, glutathione redox imbalance, and pro-inflammatory activation. These findings suggest that 6PPD and 6PPD-Q may contribute to lipid-metabolism-related toxic responses through shared and distinct processes involving oxidative stress, inflammatory activation, and lipid dysregulation. These results provide preliminary mechanistic insights into their metabolic toxicity and support further experimental evaluation for environmental health risk assessment.