A Study on Insulin Levels and the Expression of Glut 4in Streptozotocin (STZ) Induced Diabetic Rats Treated with Mustard Oil Diet.

Abstract

The study was undertaken to evaluate the therapeutic effect of mustard oil incorporated diet in streptozotocin (STZ)-induced type 1 diabetic rats. Dietary composition has shown to play a significant role in improving insulin sensitivity. Various authors have reported the hypoglycemic effect of mustard oil in experimentally induced diabetic rats. In the present study,reverse transcriptase polymerase chain reaction (RT-PCR) was done to analyze the Glut 4 expression in STZ induced diabetic rats as it is a key player in glucose homeostasis. The effect of mustard oil on serum biochemical parameter and insulin levels was also studied. Twenty-four male Wistar rats were randomly divided into three different groups with each containing eight animals. The first, second and third groups were control, diabetic control and treatment group with mustard oil respectively. All the rats in respective groups were fed for 60days with iso-caloric mash diet containing 8% lipid. Diabetes was induced by intra-peritoneal administration of STZ (40mg/kg body weight). A highly significant reduction in blood glucose level, with an increase in insulin activity was observed in mustard oil-treated diabetic rats when compared to control group indicating anti-hyperglycemic activity of mustard oil. Mustard oil-treated diabetic rats showed increased expression of Glut 4 in muscle tissue when compared to diabetic control. A significant reduction in the levels of triacylglycerols, total cholesterol, VLDL and LDL and raised plasma HDL were noticed in mustard oil-treated diabetic rats when compared to diabetic control rats. Histopathological studies revealed a mild regeneration of β cells of pancreas in mustard oil-treated diabetic rats. The results from our investigation suggest that mustard oil elicits hypoglycemic effect by increased insulin activity and up-regulation of Glut 4 gene expression in muscle tissue of STZ-induced diabetic rats.