Ameliorative effect of polydatin on hyperglycemia and renal injury in streptozotocin-induced diabetic rats

To investigate the effect of polydatin on glucose transporter, blood glucose homeostasis and renal injury in streptozotocin (STZ)-induced diabetic rats. The in vitro inhibitory effect of polydatin on sodium-glucose cotransporter-1 (SGLT1) and 2 (SGLT2) was determined using HEK293 cells. The inhibitory effect of polydatin on GLUT1 and GLUT4 was evaluated using 3T3-L1 adipocytes. Streptozotocin-induced diabetic rats were used for this study. Fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), urea nitrogen, serum creatinine and urinary protein were determined using biochemical analyzer. Histopathological examination was performed on renal tissue. Serum levels of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), monocyte chemoattractant protein 1 (MCP-1) and C-reactive protein (CRP) were also determined. Polydatin significantly inhibited SGLT1/2 and exhibited high selectivity for both GLUT1 and GLUT4. It significantly and dose-dependently decreased hyperglycemia, enhanced urine glucose excretion in the diabetic rats. The polydatin treatment significantly ameliorated symptoms of DN such as polyuria, polydipsia and hyperphagia. The hypoglycemic effect of polydatin was maintained throughout the treatment period. In addition,the levels of IL-1β, TNF-α, MCP-1 and CRP were significantly reduced in treated group. Treatment with polydatin significantly ameliorated most of the structural and morphological changes induced by STZ. Moreover, the levels of urinary protein, serum creatinine and urea nitrogen were significantly reduced after treatment with polydatin. As a potential dual inhibitor of SGLT1/2, polydatin has high selectivity for GLUT1 and GLUT4. Its long-term administration delays the development of DN, protects renal function and ameliorates renal tissue injury.