Pathophysiological Changes in Pre-Diabetic Stage of Spontaneously Diabetic Torii (SDT) Rats

The Spontaneously Diabetic Torii (SDT) rat is a new model of non-obese type 2 diabetes. In the present study, researchers investigated pathophysiological changes of male SDT rats in pre-diabetic stage from 8-16 weeks of age. In oral glucose tolerance test at 12 weeks of age, SDT rats showed glucose intolerance and decrease of glucose-stimulated insulin secretion. Different doses of Streptozotocin (STZ) were administered to SDT rats or SD rats and the pancreatic weakness was examined. SDT rats treated with STZ at a dose level of 20 mg kg-1 were diabetic within 1 week after treatment whereas SD rats got the diabetes after 30 mg kg-1 STZ was received. Insulin tolerance test was performed at 8, 16 and 24 weeks of age in order to examine the insulin sensitivity and the K value was calculated. Interestingly in SDT rats at 16 weeks of age, insulin sensitivity was increased as compared with that in SD rats. Pathohistological changes in pancreas such as atrophy of islets, multiple irregular projection of islets and islet fibrosis were observed in SDT rats at 15 weeks of age. In this study, SDT rat is a useful model for the analysis of the progression of pre-diabetes and the onset of type 2 diabetes.