Background: Decreased expression of α3β1 integrin may contribute to reduction in podocyte adhesion to glomerular basement membrane (GBM), which represents a novel early mechanism leading to diabetic kidney disease (DKD). Here, we examined the protective effects of Notoginsenoside R1 (NR1) on podocyte adhesion and α3β1 integrin expression under diabetic condition in vitro and in vivo.
Methods: Conditionally immortalized mouse podocytes were exposed to high glucose (HG) with 10 and 100μg /ml of NR1 for 24 h. Podocyte adhesion, albuminuria, oxidative markers, renal histopathology, podocyte number per glomerular volume, integrin-linked kinase (ILK) activity and α3β1 integrin expression were measured in vitro and in vivo.
Results: HG decreased podocyte adhesive capacity and α3β1 integrin expression, the main podocyte anchoring dimer to the GBM. However, NR1 ameliorated impaired podocyte adhesive capacity and partially restored α3β1 integrin protein and mRNA expression. These in vitro observations were confirmed in vivo. In streptozotocin(STZ)-induced diabetic rats, treatment with NR1 (5 and 10 mg· kg(-1)· d(-1)) for 12 weeks partially restored the number of podocytes per glomerular volume and glomerular α3β1 integrin expression, as well as ameliorated albuminuria, histopathology and oxidative stress. NR1 also inhibited glomerular ILK activity in diabetic rats.
Conclusion: NR1, a novel antioxidant, ameliorated glucose-induced impaired podocyte adhesive capacity and subsequent podocyte depopulation partly through α3β1 integrin upregulation. These findings might provide a potential new therapeutic option for the treatment of DKD.