To investigate the therapeutic potential and renal protective mechanisms of hirsutine in diabetic kidney disease (DKD).A DKD model was induced in Sprague-Dawley rats using a high-fat diet (HFD) and streptozotocin (STZ). High glucose (HG)-stimulated HK-2 cells served as an in vitro model. Reactive oxygen species (ROS) levels in kidney tissues were measured using dihydroethidium (DHE) staining. ELISA was performed to measure MDA, SOD, and GSH in both rat tissues and HK-2 cells. Western blot and immunofluorescence analyses evaluated renal fibrosis, the Nrf2 signaling pathway, and autophagy-related proteins (Beclin 1, LC3I/II, P62).Hirsutine treatment significantly improved metabolic and renal parameters in rats, enhancing renal function and reducing fibrosis, as shown by lower levels of Vimentin, Collagen-IV, and α-SMA. It alleviated oxidative stress, indicated by reduced ROS and MDA levels and increased SOD and GSH activity. Additionally, hirsutine enhanced autophagy, reflected by higher Beclin 1 and LC3I/II levels and decreased P62 expression. By disrupting the Keap1-Nrf2 interaction, hirsutine increased Nrf2 levels and upregulated antioxidative enzymes like NQO1, SOD-2, and HO-1.Hirsutine exhibited renoprotective effects in DKD by modulating the Keap1/Nrf2 pathway, mitigating oxidative stress and promoting autophagy, making it a promising candidate for treatment.Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.