Comparison of Three Different Glucose-lowering Drugs on Serum Levels of Glucose and Pancreas Histopathology in Streptozotocin-Induced Diabetic Rats

Introduction: Diabetes mellitus is a metabolic disorder resulting from a defect in insulin secretion, insulin action, or both. The aim of the present study was to compare the effect of three different blood glucose-lowering drugs in streptozotocin-induced diabetic rats. Materials and methods: A total of 60 male Wistar rats (220–250 g and 2-3 months of age) were selected for the current study, and they then were divided into five equal groups. Group 1 included healthy control rats receiving standard diet, group 2 involved diabetic rats receiving standard diet plus acarbose (25mg/kg/day) via gastric feeding tube daily for 8 weeks, group 3 embraced diabetic rats receiving standard diet plus pioglitazone (1 mg/kg/day) via gastric feeding tube daily for 4 weeks, and group 4 received of diabetic rats receiving standard diet plus repaglinide (10 mg/kg/day) via gastric feeding tube daily for 4 weeks. Diabetes was induced by intraperitoneal injection of streptozotocin at a dosage of 65 mg/kg body weight. At the end of the study, the samples were taken for histopathological investigation of pancreas and serum glucose levels. The mean diameter of pancreatic islets and the percentage of beta and alpha cells were calculated in all groups. Results: The fasting blood glucose in three treated and normal control rats was significantly less than the diabetic control group. One hour after treatment the blood glucose level reduced significantly in three treated and normal control rats compared to the diabetic control group. On day 7, the percentage of alpha cells in the pioglitazone and acarbose groups increased significantly, compared to the diabetic control group. On day 28, the percentage of beta cells in the treated groups increased significantly, compared to normal and diabetic control groups. Moreover, the mean of islet diameter in the treated groups increased significantly, compared to the normal and diabetic control groups. The percentage of alpha cells in the repaglinide group significantly reduced on day 28, compared to the diabetic control group. Conclusion: Among the administrated drugs, pioglitazone had the most positive effects on controlling blood glucose, increasing beta cells as well as improving the diameter of pancreatic islets.