Abstract
BACKGROUND: Acute kidney injury (AKI) results from cisplatin chemotherapeutic agents in 30 %-46 % of patients, but clinically effective preventive and therapeutic approaches are lacking. Bone marrow mesenchymal stem cells-derived exosomes (BMSCs-exo) have potential in tissue repair, but the mechanism by which they attenuate cisplatin-induced kidney injury is unknown. OBJECTIVE: To explore the therapeutic effect of BMSCs-exo on cisplatin-induced AKI and to analyze the key molecular mechanism involved. METHODS AND MATERIALS: BMSCs-exo were extracted via ultracentrifugation and identified via transmission electron microscopy, nanoparticle analysis and Western blot. C57BL/6 mice were divided into a control group (Con), a cisplatin model group (Cis), and a BMSCs-exo treatment group (BMSCs-exo), and renal function was dynamically tested. PAS staining was used to observe histopathological changes in mouse kidney tissues, while immunohistochemistry was employed to assess the expression levels of Wnt4, β-catenin, FZD5, CD31, and the tubular injury markers NGAL and KIM1. Western blot was used to detect the expression of Wnt4, β-catenin, FZD5 and CD31. High-throughput sequencing was used to screen for differential miRNAs, and GO/KEGG enrichment analysis of target genes was performed. RESULTS: Blood creatinine and urea nitrogen levels were significantly higher in the Cis group than in the Con group, and renal tubular epithelial cells exhibited necrosis, confirming successful AKI model establishment. BMSCs-exo alleviated renal dysfunction, histopathological alterations, and tubular injury in vivo, as evidenced by NGAL and KIM1 expression. We further demonstrated that BMSCs-exo specifically localized to the injured kidney. MiRNA sequencing of renal tissues from the Con, Cis and BMSCs-exo groups identified mmu-miR-874-3p-enriched in Wnt signaling and angiogenesis pathways-as a key mediator of the renoprotective effects of BMSCs-exo, with FZD5 as its downstream target. Moreover, treatment with BMSCs-exo markedly prevented microvascular loss. In the BMSCs-exo group, Wnt4, β-catenin and CD31 expression were upregulated, whereas FZD5 expression was downregulated, consistent with the immunohistochemistry results. CONCLUSIONS: BMSCs-exo protect kidneys against cisplatin-induced AKI(Cis-AKI) by attenuating injury to the renal microvasculature and tubule epithelial cells, primarily through mmu-miR-874-3p-mediated inhibition of FZD5 activation and promotion of Wnt/β-catenin pathway activation.