Exploring the Potential Mechanisms Linking Bisphenol A Exposure to Atrial Fibrillation: An Integrated Multi-Dimensional Analysis from Network Toxicology to In Vivo Validation

Atrial fibrillation (AF) is the most common clinical arrhythmia with complex pathogenesis and limited therapeutic options. The pro-arrhythmic effect of environmental endocrine disruptor bisphenol A (BPA) remains unclear. This study integrated network toxicology, Mendelian randomization (MR), molecular docking, molecular dynamics simulations, single-cell transcriptomics and in vivo rat experiments to construct a multi-dimensional evidence chain for exploring BPA-mediated AF mechanisms and key intervention targets. We screened 206 shared targets of BPA and AF, which were enriched in endocrine resistance, phosphoinositide 3-kinase-protein kinase B, and lipid-metabolism pathways. Protein–protein interaction and two-sample MR analyses, supported by genetic evidence, suggested cystatin C (CST3) as a potential risk factor for AF, while glutathione S-transferase A1 (GSTA1) and placental growth factor (PGF) served as potential protective factors. Molecular docking confirmed favorable binding activities between BPA and core targets (binding energy < −5.0 kcal/mol), and 100 ns molecular dynamics simulations verified stable complex conformations under physiological conditions. Single-cell transcriptomics revealed cell-type-specific expression of target genes: CST3 in immune and stromal cells, GSTA1 in smooth muscle cells and fibroblasts, and PGF predominantly in smooth muscle cells. Further experiments in Sprague–Dawley rats demonstrated that BPA exposure increased AF inducibility, upregulated atrial CST3, down-regulated GSTA1 and PGF, and aggravated atrial fibrosis and inflammatory infiltration. Collectively, BPA may promote AF by interfering with the functions of CST3, GSTA1, and PGF. This study provides evidence for the pro-arrhythmic effects of environmental pollutants and theoretical references for targeted prevention and treatment of AF.