Exploring the mechanism of Qingre Yishen Xiaozheng formula in treating diabetic kidney disease via the HIF-1α/HO-1 signaling pathway: an integrated network pharmacology and experimental study.

Ethnopharmacological relevance: The Qingre Yishen Xiaozheng Formula (QRYSXZF) is a traditional Chinese medicine prescription developed based on the "clearing heat and resolving stasis" principle, clinically applied for the treatment of diabetic kidney disease (DKD). Aim of the study: To investigate the therapeutic effects of QRYSXZF on DKD and elucidate its underlying mechanisms through integrated network pharmacology and experimental validation, focusing on the HIF-1α/HO-1 signaling pathway and ferroptosis regulation. Materials and methods: Active components of QRYSXZF were screened using the TCMSP database (OB ≥ 30%, DL ≥ 0.18), and a herb-compound-target network was constructed via Cytoscape 3.8.0. DKD-related targets were retrieved from GeneCards, OMIM, and TTD databases. Protein-protein interaction (PPI) networks, GO/KEGG enrichment analyses, and molecular docking (PyMOL/AutoDock) were performed to predict core targets and pathways. In vivo, a DKD rat model was established by unilateral nephrectomy combined with streptozotocin (STZ) injection, followed by 12-week QRYSXZF treatment. Renal function markers (BUN, 24h-UTP, KIM-1, NGAL), oxidative stress (SOD, MDA, GSH-Px), iron metabolism (SI, SF, TF), and ferroptosis-related proteins (GPX4, ACSL4, FTH1, NCOA4) were analyzed. Histopathological changes were assessed by H&E, PAS, and Masson staining, while HIF-1α/HO-1 pathway activity was evaluated via Western blot. Results: Network pharmacology identified 153 shared targets between QRYSXZF and DKD, with quercetin, kaempferol, and β-sitosterol as core active components, while KEGG analysis highlighted the HIF-1 signaling pathway as a key mechanism. In DKD rats, QRYSXZF significantly improved renal function by reducing BUN, Cys-C, KIM-1 and NGAL, attenuated oxidative stress through increasing SOD/GSH-Px and decreasing MDA, regulated iron metabolism by lowering SF and elevating TF, suppressed ferroptosis via upregulating GPX4/FTH1 and downregulating ACSL4/NCOA4, and inhibited HIF-1α/HO-1 pathway activation, with molecular docking confirming stable binding between QRYSXZF components and HIF1A/HMOX1. Conclusion: QRYSXZF alleviates DKD progression by modulating the HIF-1α/HO-1 pathway to reduce ferroptosis, oxidative stress, and iron overload, providing a scientific basis for its clinical application in DKD management.