Integrating network toxicology and experimental validation to elucidate the molecular mechanism basis of chondrotoxicity of Benzo[a]pyrene in osteoarthritis

Benzo[a]pyrene (BaP), a widespread environmental pollutant, has been increasingly implicated in the pathogenesis of chronic degenerative diseases. Environmental pollutants have recently been recognized as emerging risk factors for osteoarthritis (OA), but the molecular mechanisms by which BaP contributes to OA progression remain unclear. This study employed an integrated strategy combining network toxicology, transcriptomic analysis, machine learning, molecular docking, dynamics simulations, and in vitro validation to systematically elucidate the role of BaP in OA progression. We identified 27 common targets shared between BaP exposure and OA, functionally enriched in cellular senescence, stress response, and metabolic dysregulation. Machine learning algorithms screened five high-confidence diagnostic biomarkers (FASN, PIEZO2, NGEF, BTG2, TNC), and a predictive nomogram was constructed. Through multi-algorithm integration, FASN was pinpointed as the core target. Molecular docking and dynamics simulations confirmed stable and favorable binding between BaP and FASN. In vitro experiments demonstrated that BaP exposure induced dose- and time-dependent chondrocyte cytotoxicity, increasing oxidative stress and lipid peroxidation by upregulating FASN expression. Furthermore, BaP potently induced chondrocyte senescence, significantly increasing the upregulation of senescence-associated proteins p53 and p21, thereby causing chondrocyte damage. Critically, pharmacological inhibition of FASN by C75 effectively mitigated these detrimental effects, restored extracellular matrix homeostasis, and alleviated BaP-induced chondrocyte senescence. Collectively, our findings reveal FASN as a pivotal molecular core mediating BaP-induced chondrotoxicity and OA progression, providing novel insights into the environmental etiology of OA and identifying a potential target for therapeutic intervention.