Lingmei Jia,1,* Siqi Yang,1,* Jun Yin,2 Ouhua Feng,2 Min Jia,1 Zhigang Wang1 

1Cardiovascular Medicine Department, The Second Hospital of Hebei Medical University, Shijiazhuang, People’s Republic of China; 2Cardiovascular Medicine Department, Jingxing County Hospital, Shijiazhuang, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Min Jia; Zhigang Wang, Cardiovascular Medicine Department, The Second Hospital of Hebei Medical University, Shijiazhuang, People’s Republic of China, Tel +86-13732219367 ; +86-15131127511, Email jiamin10086@163.com; 15131127511@163.com

Objective: This study aimed to investigate the protective effect of bergenin on myocardial ischemia/reperfusion (I/R) injury and to elucidate its underlying mechanism.
Methods: The in vivo model of myocardial I/R injury was established by transient ligation of the left anterior descending coronary artery in Sprague-Dawley rats, which were divided into sham, I/R, I/R+bergenin, and I/R+bergenin+erastin (an agonist of ferroptosis) groups.After the model was established, the rats underwent echocardiography to assess the cardiac function. Hematoxylin and eosin (HE) staining and Masson’s trichrome staining were performed to evaluate the cardiac pathological damage. Malondialdehyde (MDA), reactive oxygen species (ROS), glutathione (GSH) and iron levels were measured to determine the ferroptosis level. Western blotting was used to detect the expression of related proteins. Next, H9C2 cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to mimic the in vitro model of myocardial I/R injury. EX527, a SIRT1 inhibitor, was used to further explore the role of SIRT1 in the myocardial protection of bergenin. In this part of the experiment, H9C2 cells were divided into four groups: control, OGD/R, OGD/R+bergenin, and OGD/R+bergenin+EX527.
Results: In vivo experiments, we found that the I/R group showed obvious myocardial pathological damage, oxidative stress and ferroptosis, while the bergenin pretreatment group reversed the above myocardial injury, but this protective effect was inhibited by the ferroptosis inducer erastin. In vitro experiments, compared with the OGD/R group, the bergenin group reduced the oxidative stress level, mitochondrial dysfunction and ferroptosis of H9C2 cells. We found that the protective effect of bergenin on the myocardium was abrogated by EX527. Moreover, Western blotting showed that bergenin activated SIRT1, and increased the phosphorylation of AMPK and the expression level of PGC-1α.
Conclusion: Bergenin exerted a protective effect on the myocardium by modulating the ferroptosis process during myocardial I/R injury through the SIRT1/AMPK/PGC-1α pathway.

Keywords: myocardial ischemia-reperfusion injury1, Bergenin2, ferroptosis3, SIRT14, AMPK5