Abstract

Background Type 2 Diabetes Mellitus (T2DM) and AF (Atrial Fibrillation) frequently coexist, amplifying cardiovascular risks via shared mitochondrial dysfunction involving metabolic dysregulation, oxidative stress, and inflammation. While the SGLT2 inhibitor dapagliflozin (DAPA) demonstrates cardiorenal protection through mitochondrial improvement, its direct mechanistic actions in T2DM-AF patients remain unknown. Our study aimed to elucidate DAPA's mitochondrial regulatory mechanisms in T2DM-AF to break the vicious cycle of mitochondrial dysfunction remodelling, addressing an unmet clinical need in this high-risk population. Methods The high-glucose atrial fibrillation (HG-AF) model was established using 30 mM glucose combined with 10 Hz electrical stimulation, followed by validation through glucose uptake assay, electrophysiology, and fibrosis-related protein and calcium transient analysis. Mitochondrial function was evaluated using ROS/JC-1 probes, ATP quantification, and mitochondrial-related protein expression. To investigate the role of DAPA, we assessed its activation of the AMPK/PGC-1α/SIRT3 signalling pathway via western blot and further confirmed the mechanism using the AMPKα inhibitor Compound C. In addition, a mouse model of HG-AF was established to further validate the in vitro results. Results Cell experiments showed that after treatment with 30 mM glucose and 10 Hz electrical stimulation, HL-1 cells exhibited increased 2-NBDG uptake, decreased Fluo-4 AM intensity, upregulation of glucose transporters and fibrosis-related proteins, and disrupted electrophysiological protein expression, confirming the successful establishment of the HG-AF model. DAPA treatment attenuated fibrosis, restored electrophysiological protein expression, decreased Drp1, and increased OPA1 and SOD2 levels. It also enhanced Fluo-4 AM intensity, reduced ROS, improved JC-1 aggregates, and boosted ATP production. In vivo experiments further confirmed that in HG-AF mice, the duration