Ferroptosis, a form of regulated cell death process, play an important role in myocardial ischemia‒reperfusion (I/R) injury. Glycyrrhizin (GL), a natural glycoconjugate triterpene, has the property to improve growth rate, immune regulation, antioxidant, anti-inflammatory. However, whether GL can attenuate myocardial I/R injury by modulating ferroptosis or other mechanisms are still unclear. In this study, SD rats underwent in vivo myocardial ischemia/reperfusion (I/R) surgery, while H9C2 cells were subjected to the hypoxia/reoxygenation (H/R) model for in vitro experiments. In addition, TAK-242, a TLR4-specific antagonist, and GL were also used to evaluate the effect and mechanisms of GL on the cardiac function and expression of ferroptosis-related gene and protein in vivo and vitro. The results show that GL decreased not only the expression of the inflammation-related factors (HMGB1, TNF-α, IL-6, IL-18 and IL-1β), but also reduced the number of TUNEL-positive cardiomyocytes, and mitigated pathological alterations in I/R injury. In addition, GL decreased the levels of MDA, promoted antioxidant capacity such as GSH, CAT, Cu/Zn-SOD, Mn-SOD, and SOD in vivo and vitro. More importantly, GL and TAK-242 regulate ferroptosis-related protein and gene expression in I/R and H/R model. Surprisingly, GL may ameliorate cardiomyocyte ferroptosis and ultimately improves cardiac function induced by H/R via the HMGB1-TLR4-GPX4 axis. Therefore, we have highlighted a novel mechanism by which GL regulates inflammation, oxidative stress, and ferroptosis via the HMGB1-TLR4-GPX4 pathway to prevent myocardial I/R injury. GL appears to be a potentially applicable drug for the treatment of myocardial I/R injury.

铁死亡是一种受调节的细胞死亡过程，在心肌缺血再灌注（I/R）损伤中发挥重要作用。甘草甜素（GL）是一种天然糖复合物三萜，具有提高生长速度、免疫调节、抗氧化、抗炎等作用。然而，GL是否可以通过调节铁死亡或其他机制减轻心肌I/R损伤仍不清楚。本研究中，SD大鼠接受体内心肌缺血/再灌注（I/R）手术，而H9C2细胞则采用缺氧/复氧（H/R）模型进行体外实验。此外，还利用TLR4特异性拮抗剂TAK-242和GL在体内外评价GL对心脏功能以及铁死亡相关基因和蛋白表达的影响和机制。结果显示，GL不仅降低炎症相关因子（HMGB1、TNF-α、IL-6、IL-18和IL-1β）的表达，而且减少TUNEL阳性心肌细胞的数量，减轻病理学改变。 I/R 损伤的改变。此外，GL还能降低体内和体外MDA水平，促进GSH、 CAT、Cu/Zn-SOD、Mn-SOD和SOD等抗氧化能力。更重要的是，GL和TAK-242在I/R和H/R模型中调节铁死亡相关蛋白和基因的表达。令人惊讶的是，GL 可以改善心肌细胞铁死亡，并最终通过 HMGB1-TLR4-GPX4 轴改善 H/R 诱导的心脏功能。因此，我们强调了GL通过HMGB1-TLR4-GPX4通路调节炎症、氧化应激和铁死亡以预防心肌I/R损伤的新机制。GL似乎是治疗心肌I/R损伤的潜在适用药物。