The Effect Of Silibinin On The Expression Of Vascular Endothelial Growth Factor (vegf) And The Type Iv Collagen In Human Podocytes Induced By High Glucose

Objective: To explore the effects of silibinin on the expression of vascular endothelial growth factor (VEGF) and the secretion of type IV collagen in normal immortalized human podocytes induced by high glucose (HG).Methods: The normal immortalized human podocytes were cultured at 33℃and allowed to differentiate at 37℃for 2 weeks. The differentiated podocytes were incubated with medium (1%FBS and 5.5mmol/L D-glucose) for 24 hours to synchronize cell growth. Podocytes were divided into several groups: 1. High glucose (30mmol/L D-glucose) was given on different time course (0h, 24h, 48h, and 72h). 2. The podocytes were divided into seven groups of normal medium (NG, 5.5mmol/L D-glucose), mannitol (MN, 24.5mmol/L mannitol plus 5.5mmol/L D-glucose), high glucose (HG, 30mmol/L D-glucose), HG plus low concentration of silibinin (HG+LS, silibinin5μg/ml), HG plus medium concentration of silibinin(HG+MS, silibinin10μg/ml),HG plus high concentration of silibinin(HG+HS, silibinin20μg/ml), and HG plus DMSO (HG+D, DMSO1mg/ml). These groups were incubated for 48h. The expressions of VEGF mRNA and protein in podocytes were detected by semiquantitative reverse transcription-PCR and Western blot analysis respectively. The concentrations of collagen IV in culture supernatant secreted by the podocytes were determined by ELISA.Results: 1. Compared with 0h group, high concentration of glucose increased the expressions of VEGF and collagen IV in podocytes in a time-dependent manner (P<0.05 or P<0.01). 2. Compared with NG group, the levels of VEGF and collagen IV expression were increased markedly after HG treatment for 48 hours (P<0.01). Compared with HG group, the different concentrations of 5, 10, 20μg/ml silibinin effectively suppressed HG-induced expressions of VEGF mRNA, VEGF protein and the secreted collagen IV in a dose-dependent manner (P<0.05).Conclusion: High concentration of glucose increases the expressions of VEGF and collagen IV by podocyte. Silibinin may exert a protective effect on podocyte and the effects of prevention and treatment on diabetic nephropathy via reducing the over-expressions of VEGF and collagen IV induced by HG.