Trimetazidine Attenuates Ischemia/Reperfusion-Induced Myocardial Ferroptosis by Modulating the Sirt3/Nrf2-GSH System and Reducing Mitochondrial Oxidative Stress

Abstract Background and Purpose： Ferroptosis is a newly defined mode of cellular demise. Increasing investigatieon supports the hypothesis that ferroptosis is a crucial factor in the complex mechanisms of myocardial ischemia-reperfusion(I/R) injury. Hence, the pursuit of ferroptosis as a therapeutic approach has promise in the management of myocardial damage. Although evidence suggests that trimetazidine (TMZ) is potentially efficacious against myocardial injury, the exact mechanism of this efficacy is yet to be fully elucidated. The objective of this work is to determine whether TMZ can act as a ferroptosis resistor and affect I/R-mediated myocardial injury. Methods： We constructed in vitro and in vivo models of I/R using H9C2 cardiomyocytes, primary cardiomyocytes, and SD rats. The optimal concentration of TMZ was determined by CCK8 and LDH experiments. Ferroptosis was confirmed by detecting the levels of GSH, lipid peroxidation ,and Fe 2+ , and the morphological alterations of mitochondria under transmission electron microscopy. Western blotting, RT-qPCR, and immunofluorescence staining were performed to detect the expression of iron death-related markers, including GPX4, SLC7A11, ACSL4, TFRC, and FTH. The Sirt3/Nrf2 pathway, which is associated with ferroptosis, was detected by Western blotting. We investigated the effects of Sirt3 molecules on TMZ-mediated inhibition of ferroptosis and cardioprotection by interfering with Sirt3 expression or activity using si-Sirt3 or 3-TYP (inhibitor of Sirt3 activity). Results: I/R mediated the onset of myocardial ferroptosis in vitro and in vivo, as reflected by excessive iron aggregation, GSH depletion, and the increase in lipid peroxidation. TMZ largely reversed this alteration and attenuated myocardium injury. Mechanistically, TMZ upregulated the expression of Sirt3. The use of si-Sirt3 and 3-TYP partly mitigated the inhibitory effect of TMZ on I/R-mediated ferroptosis and upregulated the expression of Nrf2 and its downstream target, GPX4-SLC7A11. Conclusions: TMZ attenuates I/R-mediated ferroptosis by activating the Sirt3-Nrf2/GPX4/SLC7A11 signaling pathway.