Development of Wistar rat model of insulin resistance

AIM: To establish a simplified and reliable animal model of insulin resistance with low cost in Wistar rats. METHODS: Wistar rats were treated with a high fat emulsion by ig for 10 d. Changes of the diets, drinking and body weight were monitored every day and insulin resistance was evaluated by hyperinsulinemic-euglycemic clamp techniques and short insulin tolerance test using capillary blood glucose. Morphologic changes of liver, fat, skeletal muscles, and pancreatic islets were assessed under light microscope. mRNA expressions of GLUT2 and alpha-glucosidase in small intestine epithelium, GLUT4 in skeletal muscles and Kir6.2 in beta cell of islets were determined by in situ hybridization. RESULTS: K(ITT) was smaller in treated animals (4.5+/-0.9) than in untreated control Wistar rats (6.8+/-1.5), and so was glucose injection rate. Both adipocyte hypertrophy and large pancreatic islets were seen in high fat fed rats, but no changes of skeletal muscles and livers were observed. mRNA levels of GLUT2, alpha-glucosidase in small intestinal epithelium and Kir6.2 mRNA in beta cells of islets increased, whereas that of GLUT4 in skeletal muscles decreased in high fat fed group compared with normal control group. CONCLUSION: An insulin resistance animal model in Wistar rats is established by ig special fat emulsion.