Oxidative stress-mediated tetrabromobisphenol A disrupts mitochondrial function in HepG2 cells and activates ferroptosis signalling to induce apoptosis

Tetrabromobisphenol A (TBBPA), a brominated flame retardant extensively used in consumer electronics, has been classified as a persistent environmental contaminant. While TBBPA-induced mitochondrial dysfunction is implicated in apoptosis, the precise oxidative stress-mediated mechanisms remain incompletely characterized. In this study, using human liver cancer cells (HepG 2 ) as an in vitro model, we systematically investigated TBBPA's mitochondrial toxicity and associated cell death pathways. In vitro assays demonstrated that 10 μM TBBPA induced approximately 50 % cell death and reduced cell viability. This treatment also markedly elevated intracellular reactive oxygen species (ROS) levels. A comprehensive analysis of mitochondrial function, including assessments of mitochondrial membrane potential (MMP), oxygen consumption rate (OCR), ATP production, respiratory chain complex activities, and mitochondrial autophagy markers (LC3B, PINK1, Parkin), revealed that TBBPA entry into cells resulted in mitochondrial dysfunction. Furthermore, Ferroptosis biomarkers quantification further revealed TBBPA-driven Fe 2+ and malondialdehyde (MDA) accumulation, coupled with upregulated expression of ferroptosis-related proteins (GPX4, SLC7A11, COX-2, Beclin-1). These findings provide novel insights into the molecular pathways underlying TBBPA-induced cytotoxicity.