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Ferroptosis is an important form of myocardial cell death in myocardial ischemia-reperfusion injury (MIRI). Naringenin (NAR), as a flavonoid, has a significant advantage in improving MIRI. But the regulatory effect and mechanism of NAR on ferroptosis in MIRI have not been reported. After the rats were given NAR and induced to form myocardial ischemia-reperfusion (MI/R) injury, Tetrazolium chloride (TTC) staining was used to detect the myocardial infarction area of rats, and Hematoxylin-eosin (H&E) staining was used to detect myocardial injury. The markers of tissue inflammation were detected by ELISA. Serum creatine kinase Serum creatin kinase (CPK), Lactate dehydrogenase (LDH), and lipid peroxide (LPO) and oxidative stress related levels were measured. In addition, iron detection kits were used to detect total iron and Fe2+ levels in cardiac tissues, and western blot was used to detect the expression of ferroptosis-related proteins and the expression of nuclear factor-erythroid factor 2-related factor 2 (Nrf2) and glutathione peroxidase 4 (GPX4). At the cellular level, H9C2 cardiomyocytes were induced by hypoxia/reoxygenation (H/R), and ferroptosis inducer Erastin was administered to detect cell viability, ferroptosis-related indicators, oxidative stress related indicators, and expressions of Nrf2 and GPX4, to explore the mechanisms involved. NAR alleviated MI/R-induced pathological damage, inflammation and lipid peroxidation in myocardial tissue of rats. NAR adjusted the NRF2 /System xc – /GPX4 axis and improved ferroptosis. At the cellular level, ferroptosis inducer Erastin reversed the protective effect of NAR on H/R-induced H9C2 cardiomyocytes. In conclusion, NAR can alleviate MIRI by regulating the Nrf2/System xc-/GPX4 axis to inhibit ferroptosis.

Objectives: Although Baduanjin (a traditional Chinese physical activity) has been reported to promote general health, the optimal exercise intensity and kinematic characteristics of this intervention remain poorly understood. This investigation aimed to quantify and compare the exercise intensities of traditional standing Baduanjin (TB) and sitting Baduanjin (SB) using cardiopulmonary exercise testing, to further clarify the sources of the previously observed benefits of this modality. Study design: Observational study. Interventions: Healthy individuals were recruited to perform TB, SB, and cycling (in order) until they reached their ventilatory threshold. Intensity-relevant parameters based on type of exercise and specific time points (exercise start and the end of the 2nd, 4th, 6th, and 8th set of motion) were compared between TB and SB with ventilatory threshold as control. Results: Forty individuals (18 male and 22 female) completed the trial. Significant differences in peak oxygen uptake, metabolic equivalent of task, and Borg scale existed among the three exercise types, indicating a decreasing overall exercise intensity in the order of ventilatory threshold, TB, and SB. All parameters except the respiratory exchange ratio fluctuated significantly across the time points. Conclusions: Both TB and SB resulted in a significantly lower exercise intensity when compared with the ventilatory threshold established through cycling exercise. The benefits of Baduanjin might be explained partly by its appropriate exercise intensity and intermittent intensity pattern. Baduanjin might be a potential alternative to existing schemes for exercise rehabilitation.