Resistant starch produces antidiabetic effects by enhancing glucose metabolism and ameliorating pancreatic dysfunction in type 2 diabetic rats

The aim of the study was to evaluate the hypoglycemic effect of low, medium, and high doses of resistant starch type 2(RS2;100, 150, and 200 g/kg) for 28 days and explore its potential mechanism of this effect in type 2 diabetic rats treated with high-glucose-fat diet and low-dose streptozotocin(STZ). RS2 treatment induced better regulation of lipid in plasma and liver, fructosamine, oral glucose tolerance test, insulin, glucose metabolism and pancreatic damage in diabetic rats. The best hypoglycemic activity was observed after the medium-dose RS2 treatment. Western blot and real-time Polymerase Chain Reaction (RT-PCR)results revealed that phosphoenolpyruvate carboxykinase and glucose-6-phosphatase are involved in glyconeogenesis in the liver, and pancreatic duodenum homeobox 1 controls gluconeogenesis balance by regulating the expression levels of glucose kinase and glucose transport protein 2 in the liver and pancreas. Furthermore, the expression levels of insulin receptor substrate 1 and insulin receptor substrate 2 were enhanced in the pancreas. Results suggested that decreases in the blood glucose levels of diabetic rats fed with RS are regulated through the alteration of the expression levels of the genes related to glucose metabolism and amelioration of pancreatic dysfunction.