Hypoglycaemic and Antilipaedemic Effects of Aqueous Extract of Cinnamon and Insulin in Streptozotocin-Induced Diabetic Rats: A Comparative Study

Diabetes mellitus is a chronic metabolic disorder which is characterized by abnormalities in carbohydrate, protein and lipid metabolism. The present study was undertaken to evaluate the comparative effects of aqueous cinnamon extract and insulin on the liver of streptozotocin-induced diabetes in Wistar rats. Twenty-four adult wistar rats weighing between 220g and 300g were used and randomly selected into four groups of six rats per group. Group A served as the normal (non-diabetic) control group that recieved feeds and water ad'libitum throughout the period of the experiment. Groups B, C, and D were induced with diabetes by intraperitoneal injection of 50mg per kilogram of body weight of streptozotocin. Group B was treated with STZ only, group C was further treated with intramuscular injection of 3 I.U of insulin (humilin R) after STZ treatment, while group D was further treated with oral administration of 300mg/kg/day of crude aqueous extract of Cinnamon after STZ for 21 days. The weights of the animals and their random blood glucose levels were measured. The animals were fasted for 12hours before they were sacrificed on day 22nd. At the end of the experiment, the animals were sacrificed and their blood collected for biochemical assay while the organ (liver) was harvested and processed for microscopy and stained using Haematoxylin and Eosin. The result revealed significant changes in weights, blood sugar levels and lipid profile of the animals in the various treatment groups. Histological changes were also seen in animals of the treated groups except for the groups A and D which features were essentially normal.

Key Words: Anti-diabetic, Diabetic mellitus (DM), Insulin and Streptozotocin (STZ)