Objective  To investigate the effect of puerarin(Pue)on ferroptosis in myocardial cells of rats with diabetic cardiomyopathy (DCM) and to analyze its potential mechanisms.

Methods  A DCM rat model was established by high-fat, high-sugar diet combined with streptozotocin injection. The successfully modeled rats were randomly divided into DCM group, low-dose Pue group (125 mg/kg, gavage), high-dose Pue group (250 mg/kg, gavage) and valsartan group (30 mg/kg, gavage), with 10 rats in each group. Another 10 healthy SD rats were selected as blank control group. At the end of treatment, fasting blood glucose, tail artery blood pressure (BP) total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) levels were measured in all groups. The cardiac function related indicatorsleft ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular end-systolic diameter (LVDs) and left ventricular end-diastolic diameter (LVDd) of rats in each group were recorded by ultrasonic apparatus. Histopathological changes in myocardial tissues were observed using hematoxylin-eosin (HE) staining and TUNEL staining. Levels of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), reactive oxygen species (ROS), malondialdehyde (MDA) and Fe²⁺were detected using enzyme-linked immunosorbent assay (ELISA) kits. Western blotting was used to detect the expression levels of glutathione peroxidase 4 (GPX4), long-chain acyl-CoA synthetase 4 (ACSL4) and proteins involved in the protein kinase B/glycogen synthase kinase-3β (AKT/GSK-3β) signaling pathway.

Results  Compared with the blank control group, the DCM group exhibited disordered or fractured myocardial fibers and significant inflammatory cell infiltration. The apoptosis rate, LVDs, LVDd, blood glucose, BP, TC, TG, LDL-C, ROS, MDA, Fe²⁺ and ACSL4 protein expression levels in the DCM group were significantly higher, and LVEF, LVFS, GSH-Px as well as SOD and the protein expression levels of GPX4, phosphorylated (p) -AKT, p-GSK-3β and p-PI3K were lower than those in the blank group (P < 0.05). Compared with the DCM group, the low-dose Pue group, high-dose Pue group and valsartan group showed reduced fractured myocardial fiber or disarray, more regular arrangement of myocardial fibers, and decreased inflammatory cell infiltration. The apoptosis rate, LVDs, LVDd, blood glucose, BP, TC, TG, LDL-C, ROS, MDA, Fe²⁺ and ACSL4 protein expression levels in the low-dose Pue group, high-dose Pue group and valsartan group were significantly lower, and LVEF, LVFS, GSH-Px as well as SOD and the protein expression levels of GPX4, p-Akt, p-GSK-3β and p-PI3K were significantly higher than those in the DCM group (P < 0.05), and the effect was more significant in the high-dose Pue group.

Conclusion  Pue treatment can effectively improve the metabolic level of DCM rats, inhibit the pathological damage and apoptosis of cardiomyocytes, alleviate oxidative stress, and thereby improving the cardiac function of DCM rats. Its mechanism of action may be related to the inhibition of cardiomyocyte ferroptosis mediated by the AKT/GSK-3β pathway.