Effects of Otostegia persica extract on serum level of glucose and morphology of pancreas in diabetic rats

With respect to antioxidant effect of Otostegia persica (O. persica) extract and the role of antioxidant agents in diabetes improvement, the aim of this study was to investigate the effect of methanolic extract of O. persica on serum level of glucose and morphology of pancreas in type I diabetic male rats. Type I diabetes was induced in male wistar rats (200-250 g) by injection of 65 mg/kg, i.p of streptozotocin. Before this and 5 days post-injection fasting blood samples were collected. Diabetes was confirmed in rats having fasting blood glucose level above 250 mg/dL. Diabetic rats were divided into 5 groups which received 100, 200 and 300 mg/kg/day O.persica extract, glibenclamide (600µg/kg) and distilled water (0.5 mL) for 14 days individually by gavage, respectively. After 14 days, fasting blood samples were collected and serum levels of glucose and insulin were measured using commercial kits by spectrophotometery and ELISA, respectively. Rat's pancreases disected out and used for histological studies after fixation, tissue preparation process and staining with hematoxylin-eosin dyes. The oral administration of O. persica extract in diabetic rats for 14 days significantly decreased glucose serum level, but it only at dose of 100 mg/kg significantly increased insulin serum level (p<0.05). Furthermore, extract improved pancreas tissue as in all doses it increased number of islets and at doses of 200 and 300 mg/kg increased the mean diameter of islets (p<0.05). Our study demonstrates that O. persica extract has a hypoglycemic effect by improving pancreas islets and increasing insulin secretion.