Multi‐organ biochemical perturbations induced by chronic benzo[b]fluoranthene exposure involve oxidative stress and inflammatory response in Balb/c mice

Abstract BACKGROUND Benzo[ b ]fluoranthene (BbF) is a bioaccumulative high‐molecular‐weight polycyclic aromatic hydrocarbon (PAH) with documented multi‐organ toxicity, yet the systemic effects of chronic oral exposure remain poorly characterized. This study tested the hypothesis that prolonged BbF exposure induces dose‐dependent oxidative and inflammatory perturbations, leading to tissue‐specific biochemical injury across major visceral organs. RESULTS Male Balb/c mice were orally exposed to 2, 8, and 16 mg kg −1 d −1 BbF for 12 weeks. BbF exposure induced dose‐dependent oxidative stress, characterized by elevated reactive oxygen species and malondialdehyde levels and decreased activities of superoxide dismutase, catalase, and glutathione peroxidase, accompanied by transcriptional downregulation of Nrf2/HO‐1 antioxidant‐related genes. Concurrently, tissue HMGB1 protein accumulated in a dose‐ and organ‐dependent manner, with hepatic HMGB1 increased by 58.32% at the highest dose, correlating with higher transcript levels of the NF‐ κ B p65/NLRP3 cascade and increased pro‐inflammatory cytokine (IL‐1 β , TNF‐ α , IL‐6) abundance. Energy metabolism was also disrupted, with high‐dose BbF reducing ATP levels by 59.52% (liver) and 55.52% (heart), and suppressing lactate dehydrogenase activity by 31.40% and 30.81%, respectively. Organ‐specific biomarkers (hepatic alanine aminotransferase/aspartate aminotransferase, renal Kim‐1, cardiac cTn‐I, splenic IgG) confirmed multi‐organ biochemical perturbations. The liver and heart showed the most pronounced changes, reflecting their intrinsic vulnerability conferred by high metabolic activity and mitochondrial abundance. CONCLUSION Chronic BbF exposure elicits dose‐dependent multi‐organ biochemical perturbations, correlating with transcriptional changes in the Nrf2/HO‐1 and NF‐ κ B/NLRP3 pathways and concurrent energy metabolism disturbance. These correlative findings provide in vivo evidence that supports hazard characterization of BbF and yields foundational data for future risk‐assessment strategies for high‐molecular‐weight PAHs. © 2026 Society of Chemical Industry.