Abstract
OBJECTIVES: To investigate the mechanism by which Guijianyu ameliorates podocyte injury in a mouse model of diabetic kidney disease (DKD) induced by advanced glycation endproducts (AGEs). METHODS: Sixty db/db mouse models of DKD were randomized equally into 5 groups for treatment with saline, Guijianyu extract at 3 doses or irbesartan for 12 weeks, and the changes in renal pathology and structure were observed using transmission electron microscopy, and the expressions of related genes and key proteins were detected using RT-qPCR and immunohistochemistry. In cultured MPC-5 cells incubated with 50 mg/L AGEs-BSA for 24 h, the effect of different concentrations of Guijianyu extract on cell viability was examined with CCK-8 assay; Western blotting was performed to detect the protein expressions of RAGE, VEGFA, TNF-α, NF-κB(p65), IL-6 and caspase-3, and the mRNA expressions of RAGE, NF-κB (p65), VEGFA and IL-6 were detected with RT-qPCR. RESULTS: In mouse models of DKD, treatment with high-dose Guijianyu extract significantly reduced renal expressions of RAGE, VEGFA, NF-κB(p65), and IL-6 proteins and the mRNA expressions of RAGE, NF-κB, and IL-6. In MPC-5 cells, exposure to AGEs significantly reduced cell viability and increased the protein expressions of RAGE, NF‑κB (p65), VEGFA, TNF-α, IL-6 and caspase-3 (P<0.05) and mRNA expressions of RAGE, NF-κB (p65), VEGFA, and IL-6. Treatment with Guijianyu extract obviously improved cell viability and reduced the expressions of RAGE, NF-κB(p65), VEGFA, TNF-α, IL-6, and caspase-3. Furthermore, Guijianyu extract effectively reversed RAGE agonist-induced elevation of protein expressions of RAGE, VEGFA, TNF-α, IL-6, and caspase-3 and mRNA expressions of RAGE, NF-κB (p65), IL-6, and VEGFA in MPC-5 cells. CONCLUSIONS: Guijianyu extract ameliorates AGEs-induced mouse renal podocyte injury in DKD by inhibiting the activation of AGEs-RAGE signaling pathway and reducing the expressions of pro-inflammatory cytokines and vascular endothelial growth factors.