Blood Glucose Level, Pancreatic Histology and Insulin-Expression in Diabetic Rats Following Metformin and Glibenclamide Administration

Metformin and Glibenclamide are used in the management of type 2 diabetes mellitus (T2DM). There is paucity of information on the efficacy of insulin expression by these anti-diabetic drugs. This study investigated the hypoglycemic, pancreatic histomorphological and insulin alterations following administration of Metformin and Glibenclamide in a T2DM model. Thirty Wistar rats were divided into six groups of five animals each. Two groups served as normal and diabetic controls respectively. Diabetes was induced with Streptozotocin (STZ). Two diabetic groups received 1.43 and 2.86 mg kg-1 body weight (bw) Metformin, while another two groups received 0.07 and 0.14 mg kg=1 bw Glibenclamide respectively. Treatments lasted for four weeks, after which animals were fasted over-night before determination of final blood glucose levels. Pancreas was dissected for histological study. Hypoglycemic effect of Glibenclamide was higher than that of Metformin. The histological features of Glibenclamide-treated rats demonstrated severe distortions, while Metformin-treated rats had mild distortions of the pancreatic islets. Insulin expression was strongly enhanced by Metformin than by Glibenclamide. In conclusion the oral therapeutic doses of Glibenclamide had a higher hypoglycemic action than Metformin. Metformin however had a stronger attenuation of diabetes-induced pancreatic distortions, and up-regulates insulin expression in diabetic rats than Glibenclimide.

Keywords: Diabetes, Glibenclamide, Metformin, blood glucose, pancreas, insulin immunohistochemistry.