Protective effect of salvianolic acid B on pancreatic islet cells in diabetic rats with fluctuating blood glucose / 中草药

ABSTRACT

Objective: To observe the protective effect of salvianolic acid B (Sal B) on pancreatic islet cells in diabetic rats with fluctuating blood glucose and the possible mechanisms implicated. Methods: Diabetes model in rats was established by feeding with high-sugar and high-fat diets combined with ip injection of streptozotocin (STZ). Then the rats were subjected to ip injection of insulin and/or ig administration of glucose at indicated time for 6 weeks to induce blood glucose fluctuation, with those in Sal B groups ig supplemented with Sal B 160 or 80 mg/kg. The contents of fasting blood glucose (FBG), fasting serum insulin (FINS), and glycosylated hemoglobin (GHb) and the levels of total anti-oxidant capacity (TAC), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) in both serum and pancreatic tissues were determined with commercially available kits. Pathological changes and cell apoptosis in pancreatic islets were evaluated by HE staining and TUNEL staining, respectively. Protein levels of PDX-1 in pancreatic tissues were examined by Western blotting analysis. Results: Compared with the control group, the contents of FBG, GHb, and MDA in diabetic rats were increased significantly, while the levels of FINS, TAC, and SOD activity were decreased markedly (P < 0.01). Pancreatic islets in diabetic rats became decreased in size and number, while cell apoptosis in islets increased notably (P < 0.01). Protein level of PDX-1 was significantly decreased in pancreas of diabetic rats (P < 0.01). Supplementation with Sal B resulted in a significant decrease in FBG, GHb, and MDA contents and increase in FINS, TAC, and SOD activity in diabetic rats (P < 0.05, 0.01). Sal B significantly attenuated pathological changes and reduced cell apoptosis in pancreatic islets of diabetic rats, with the expression of PDX-1 protein up-regulated evidently (P < 0.05 or 0.01). Conclusion: Sal B can significantly ameliorate pancreatic pathological changes and improve pancreatic islet function in diabetic rats with fluctuating blood glucose, which might be attributed to attenuation of oxidative stress, up-regulation of PDX-1 expression, and suppression of islet cell apoptosis.