Aerobic Exercise Alleviates Doxorubicin-Induced Cardiotoxicity via Inhibition of Ferroptosis.

Introduction: Doxorubicin (DOX), a potent anthracycline, is widely used in cancer therapy, but its effect is limited by doxorubicin-induced cardiotoxicity (DIC). Increasing evidence suggests that DIC is associated with ferroptosis, a cell death characterized by the iron-dependent accumulation of lipid peroxides. Although aerobic exercise is recommended for chemotherapy-related cardiac dysfunction, the extent to which its protective effects against DIC are mediated through the inhibition of ferroptosis remains largely unclear. The aim of this study was to elucidate the mechanism through which aerobic exercise attenuates DIC and provide theoretical support for promoting scientifically guided exercise in patients with DIC.

Methods: We conducted in vivo experiments involving 8 weeks of aerobic exercise during and after DOX treatment of C57BL/6J male mice, and in vitro experiments, H9c2 cells were treated with DOX and ferrostatin-1 (Fer-1, a ferroptosis inhibitor). Mice were randomly assigned into four groups: Control (C, n = 6), DOX (D, n = 10), aerobic exercise (E, n = 6) and DOX + aerobic exercise (DE, n = 10). Echocardiography was used to measure left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) to assess cardiac function in mice. ELISA kits were used to quantify serum biomarkers of myocardial injury, including cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP), and lipid peroxidation markers, such as 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA). Hematoxylin and eosin and Masson's trichrome were performed to evaluate myocardial structural damage. Fluorescent probes were used to detect ferrous iron (Fe2+), reactive oxygen species (ROS), and lipid peroxides in H9c2 cells. Western blotting was conducted to analyze ferroptosis-related proteins, including glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), acyl-CoA synthetase long-chain family member 4 (ACSL4), transferrin receptor 1 (TfR1), and ferritin heavy chain 1 (FTH1).

Results: DOX treatment significantly induced cardiac damage and dysfunction, as evidenced by disrupted myocardial tissue, increased myocardial fibrosis and cTnT levels, and decreased LVEF and LVFS. However, aerobic exercise effectively reduced cardiac structural and functional damage, and improved the rate of survival in mice. Furthermore, DOX-induced ferroptosis in cardiomyocytes both in vitro and in vivo, as marked by increased levels of Fe2+, ROS, and MDA, along with altered protein expression, including reduced FTH1 and SLC7A11 levels and increased ACSL4 levels. In contrast, aerobic exercise significantly mitigated these changes in vivo, and Fer-1 also effectively inhibited these effects in vitro.

Conclusion: Collectively, this study demonstrates that aerobic exercise alleviates DIC via the inhibition of ferroptosis.