Astragaloside IV attenuates high glucose-induced podocyte ferroptosis via the GSK3β/Nrf2/GPX4 pathway

To investigate whether AS-IV alleviates high glucose (HG)-induced podocyte ferroptosis and whether this effect is associated with the GSK3β/Nrf2/GPX4 axis.

Differentiated MPC-5 podocytes were exposed to HG (30 mmol/L) with or without AS-IV, the GSK3β inhibitor LY2090314, or the ferroptosis inhibitor Ferrostatin-1 (Fer-1). An osmotic control (mannitol) was included. Cell viability was quantified with the CCK-8 assay. Levels of reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and Fe²⁺ were measured. Lipid peroxidation was detected using C11-BODIPY 581/591. Mitochondrial morphology was examined by transmission electron microscopy and protein expression was analyzed by Western blot.

HG exposure induced podocyte injury, characterized by decreased viability, increased oxidative stress (elevated ROS, MDA and lipid ROS), GSH depletion, iron overload and mitochondrial damage. The osmotic control did not reproduce these effects. AS-IV or Fer-1 significantly attenuated the HG-induced damage and lipid peroxidation. At the molecular level, HG downregulated Nephrin, p-GSK3β (Ser9), Nrf2 and GPX4, while upregulating total GSK3β. AS-IV treatment partially reversed these protein expression changes and produced a protective pattern similar to that of LY2090314.

AS-IV alleviates HG-induced podocyte injury, possibly by suppressing ferroptosis and this protective effect may involve modulation of the GSK3β/Nrf2/GPX4 axis. The results offer new insights into DN pathogenesis and support AS-IV as a potential therapeutic candidate.