Purpurin Rescues Contrast-Induced Acute Rat Kidney Injury via Inducing Autophagy and Inhibiting Apoptosis

Objectives: Contrast-induced acute kidney injury (CIAKI) is a major cause of hospital-acquired renal injury, and strategies for its treatment are currently lacking. This study aimed to investigate the amelioration effect and mechanism of purpurin, a natural antioxidant, against CIAKI via an integrated analysis of network pharmacology, bioinformatics, molecular docking, and animal experiments. Methods: Network pharmacology approaches were used to predict key targets of purpurin against CIAKI. The differential expression of these key targets was further investigated using bioinformatics analysis and molecular binding with purpurin by molecular docking. A CIAKI model was established in SD rats via iohexol administration, and they were treated with 2.5 mg/kg or 5 mg/kg purpurin. Related physiological and pathological indexes were detected to explore the intervention mechanism. Results: Key gene targets were screened from protein-protein interaction networks, of which Pik3c2a, Esr1, Aktip, HSP90AA1, Bcl2, Caspase3, and SRC in the CIAKI group of GSE189881 were significantly differentially expressed compared to the control group. Molecular docking results show that PI3K, ESR1, HSP90, CASP3, AKTI, and SRC had the highest level of connectivity with purpurin. In vivo experiments demonstrated that the Scr and BUN increased in CIAKI rats, the pathological morphology of renal tissue deteriorated, the levels of TNF-α, IL-1β, and IL-6 increased, the contents of MOD and NO in oxidative stress increased, and the activity of SOD and GSH-PX decreased. After administration of purpurin, the above indexes improved in a dose-dependent manner (<0.05). Western blotting showed that purpurin inhibited the Beclin1/Bcl-2/caspase-3 apoptotic cascade and induced the P62/LC3 autophagy pathway. Conclusions: This study provides experimental evidence supporting purpurin as a potential therapeutic agent for CIAKI and further explores its antioxidant mechanisms.