Combination of Polydatin and Hawthorn Leave Flavonoids Ameliorate Atherosclerotic Plaque Vulnerability in ApoE-/- Mice by Regulating Ferroptosis via the Nrf2/HO-1/GPX4 Axis.

Background: Atherosclerosis (AS) is a chronic inflammatory vascular disease in which ferroptosis plays a crucial role. While the combination of polydatin (PD) and Hawthorn leaf flavonoids (HLF), termed PD and HLF combination (PH), is effective against AS, its impact on plaque vulnerability and the underlying mechanisms remain unclear.

Methods: ApoE^-/- mice were fed a high-fat diet (HFD) for 12 weeks to establish an AS model and treated with PD, HLF and Simvastatin for 8 weeks. Histological characterization of atherosclerotic lesions was performed using pathological staining. Transmission electron microscopy (TEM) was used to evaluate mitochondrial damage. Lipid peroxidation levels were assessed using ELISA. Immunofluorescence staining was performed to verify Nrf2 nuclear translocation. Expression of the Nrf2/HO-1/GPX4 axis was detected using Western blotting and PCR.

Results: HFD significantly promoted AS lesion formation and instability, and caused severe iron overload and lipid peroxidation in atherosclerotic lesions. PH significantly reduced dyslipidemia and suppressed atherosclerotic plaque progression in ApoE-/- mice. Meanwhile, the PH combination visibly reduced iron accumulation and improved mitochondrial ultrastructure. Additionally, PH combination decreased the levels of ROS, MDA, 4HNE, 8-OHdG, and Fe²⁺, while increasing GSH levels. Further studies showed that the PH combination enhanced the translocation of Nrf2 into the nucleus, HO-1, GPX4, SLC7A11, FPN1, and FTH1 expression, and inhibited cytoplasmic Nrf2 and TFR1 expression.

Conclusion: PH combination reduced the instability of atherosclerotic lesions in ApoE^-/- mice by modulating iron metabolism and lipid peroxidation through activation of the Nrf2/ HO-1/GPX4 axis.