Xueguan Ruanhua Pills improve atherosclerosis by inhibiting ferroptosis through the Nrf2/xCT/GPX4 pathway
Objective We investigated the effects of Xueguan Ruanhua Pills(XGRHW) on ferroptosis in ApoE-/- atherosclerotic mice through the nuclear factor E2 related factor 2 (Nrf2)/xCT/glutathione peroxidase 4 (GPX4) signaling pathway.Methods Ten male C57BL/6J mice in the normal group were fed normal chow. Additionally, 50 ApoE-/- mice were fed high-fat chow for 12 weeks, and were divided into the following five groups (10 mice per group): the model group, the XGRHW low-dose (2.34g/kg) group, the XGRHW high-dose (4.68 g/kg) group, the XGRHW high-dose combined with the Nrf2 inhibitor ML385 (0.03 g/kg) group, and the ferrostatin-1 (1 mg/kg) group. Drugs were administered for 6 weeks. The blood levels of four types of lipids were detected by an automatic lipid analyzer, lipid deposition in the aorta was observed by Oil Red O staining, histomorphological changes in the aortic sinus were observed by HE staining, the serum levels of Fe2+, MDA, GSH, and SOD were determined by colorimetric assays, and the expression levels of FTH1 and FTL in the aortic sinus were observed by immunofluorescence. The protein levels of Nrf2, xCT, and GPX4 in mouse aortic tissues were detected by Western blotting. The ultrastructural changes of aortic mitochondria were observed by transmission electron microscopy.Results Compared with the normal group, mice in the model group showed obvious lipid plaque deposition in the aorta, severely calcified lesions in the aortic sinus, elevated serum levels of TC, TG, LDL-C, Fe2+, and MDA, decreased levels of HDL-C, SOD, and GSH (P<0.01), and decreased protein expressions of aortic Nrf2, xCT, and GPX4 as well as the iron storage proteins FTH1 and FTL (P<0.01), and serve damage to mitochondrial structure and morphology. Compared with the model group, the relative aortic plaque area was decreased, calcified lesions in the aortic sinus were decreased, serum levels of TC, TG, LDL-C, Fe2+, and MDA were decreased, and HDL-C, SOD, and GSH levels were increased in the XGRHW low-dose and high-dose and ferrostatin-1 groups (P<0.05 or P<0.01), and Nrf2, xCT, GPX4, and the iron storage proteins FTH1 and FTL were upregulated in aortic tissues (P<0.05 or P<0.01), and mitochondrial structure approaching normal. In the XGRHW high-dose+ML385 group, compared with the XGRHW high-dose group, the levels of blood lipids and lipid peroxidation were increased and the protein levels of Nrf2, xCT, and GPX4 in aortic tissue and the iron storage proteins FTH1 and FTL were decreased (P<0.01), and mitochondrial structure was damaged indicating that ML385 could inhibit the therapeutic effect of the XGRHW in atherosclerotic mice.Conclusion The XGRHW can improve blood lipid levels and reduce the degree of arterial plaque lesions in atherosclerotic mice, and its mechanism of action may be related to activation of the Nrf2/xCT/GPX4 pathway to inhibit ferroptosis.