Ginsenoside Rb1 ameliorates myocardial ischemia/reperfusion injury in rats by inhibiting cardiomyocytes ferroptosis via the Nrf2/HO-1/GPX4 signaling pathway

Ginsenoside Rb1 (GRb1), a major representative activity substance of ginsenoside, exhibits protective effects against myocardial ischemia/reperfusion injury (MI/RI). However, its mechanism of action in MI/RI treatment remains unclear. A rat MI/RI model was established by transient ligation of the left anterior descending coronary artery for 30 min followed by reperfusion. Cardiac dysfunction and myocardial damage were assessed using cardiac hemodynamic measurements and hematoxylin and eosin staining, respectively. Serum cardiac troponin T (CTNT), creatine kinase-MB (CK-MB), and lactate dehydrogenase (LDH) levels were assessed using enzyme-linked immunosorbent assay, and malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and reactive oxygen species (ROS) levels were detected using colorimetric assays and fluorescence microscopy, respectively. Nuclear factor erythroid 2-related factor 2 (Nrf2) protein expression was detected by immunohistochemistry, and Nrf2, Heme oxygenase-1 (HO-1), Glutathione peroxidase 4 (GPX4), Acyl-CoA synthetase long-chain family member 4 (ACSL4), and Prostaglandin-endoperoxide synthase 2 (Ptgs2) protein levels in myocardial tissue lysates were monitored by western blotting. Compared to the sham group, cardiac hemodynamic coronary flow (CF), left ventricular systolic pressure (LVSP), dp/dtmin, and dp/dtmax were decreased, along with elevated serum levels of cTnT, CK-MB, and LDH, collectively indicating impaired cardiac function. Furthermore, MI/RI rats demonstrated increased myocardial oxidative stress, as evidenced by elevated ROS and MDA levels, alongside decreased activities of the SOD and CAT. Treatment with GRb1 (50 and 100 mg/kg) reversed these alterations. Compared to the sham group, MI/RI rats displayed increased myocardial expression of ferroptosis markers, including ACSL4 and Ptgs2. Conversely, protein levels of the ferroptosis-related protective pathway components Nrf2, HO-1, and GPX4 were significantly reduced in MI/RI rats. GRb1 treatment (50 and 100 mg/kg) effectively restored Nrf2/HO-1/GPX4 pathway activity and suppressed ferroptosis markers. The protective effects of GRb1 on MI/RI-induced cardiac dysfunction and injury were significantly attenuated by co-administration of an Nrf2 inhibitor (ML385), confirming the critical role of the Nrf2/HO-1/GPX4 axis in mediating the cardioprotection of GRb1. GRb1 ameliorated MI/RI in rats by inhibiting cardiomyocyte ferroptosis via the Nrf2/HO-1/GPX4 pathway. Mechanism diagram of Rb1 improving myocardial ischemia/reperfusion injury in rats