Astragaloside IV Alleviates Transferrin Receptor 1-Mediated Ferroptosis in Diabetic Nephropathy

Background: Diabetic nephropathy (DN) is a leading cause of end-stage renal disease with limited therapeutic options. Astragaloside IV (AS-IV), a saponin monomer from Radix Astragali, has been reported to exert renoprotective effects; however, the underlying mechanism remains unclear. Network pharmacology identified transferrin receptor 1 (TFRC) as a potential target of AS-IV. This study investigated whether AS-IV alleviates DN by modulating TFRC-mediated ferroptosis.Methods: A DN rat model was established via intraperitoneal injection of streptozotocin (STZ). Successfully modelled rats were randomized into three groups (n = 6 each): DN model, Ferrostatin-1 (ferroptosis inhibitor, positive control), and AS-IV (5 mg/kg/d, oral administration). A negative control group received saline. Treatments were initiated 3 weeks after STZ injection and continued for 12 weeks. To evaluate the renoprotective effects of AS-IV, we measured fasting blood glucose, renal function (serum creatinine (Scr), blood urea nitrogen (BUN), urinary albumin excretion rates (UAER)), and performed histopathological (Hematoxylin-Eosin (HE)/Masson) and TUNEL staining. To dissect the molecular mechanism, we examined ferroptosis markers (glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), ferritin heavy chain 1 (FTH-1)) by qRT-PCR, lipid peroxidation indices (malondialdehyde (MDA), 4-Hydroxynonenal (4-HNE), glutathione (GSH), iron content), and the TFRC/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) protein axis by Western blotting. For in vitro validation, HK-2 cells were exposed to high glucose, treated with AS-IV with or without TFRC overexpression, and assessed for cell viability, apoptosis, lipid peroxidation, and pathway protein expression.Results: AS-IV treatment significantly improved renal function, ameliorated renal histopathological lesions, and reduced tubular and glomerular injury scores in DN rats (p < 0.05). It also attenuated renal cell apoptosis (p < 0.001). Mechanistically, AS-IV downregulated TFRC protein expression, activated the Nrf2/HO-1 signalling axis, restored the mRNA expression of the ferroptosis-related markers GPX4, SLC7A11 and FTH-1, reduced lipid peroxidation products and iron content, and increased GSH levels (p < 0.01). In high glucose-treated HK-2 cells, AS-IV enhanced cell viability and reduced apoptosis, lactate dehydrogenase release, reactive oxygen species, Fe2+ and MDA; however, these protective effects were partially reversed by TFRC overexpression (p < 0.01).Conclusion: AS-IV alleviates renal injury and ferroptosis in DN, and this effect is associated with downregulation of TFRC and activation of the Nrf2/HO-1 pathway. These findings suggest that TFRC may be involved in the protective effects of AS-IV and warrants further investigation as a potential therapeutic target.