Nongenetic model of type 2 diabetes: a comparative study

Abstract

Seven-week-old male Sprague-Dawley (SD) rats were divided into six groups (LFC, LFD, HFC, HFD30, HFD40, HFD50) to determine whether animals receiving a low-fat (LF) diet plus nicotinamide-streptozotocin (NA-STZ) injection or animals receiving a high-fat (HF) diet plus STZ injection provide a better model of type 2 diabetes. After 2 weeks of feeding, diabetes was induced by intraperitoneal injection of NA (230 mg/kg BW) and STZ (65 mg/kg BW) in LFD, and STZ 30, 40, 50 mg/kg BW to HFD30, HFD40, HFD50 groups, respectively. Fasting blood glucose at 48-72 h and nonfasting blood glucose at 1 week after STZ injection were >200 and >600 mg/dl, respectively, in HFD40 and HFD50 groups while no significant difference was observed among other groups. Serum insulin concentration was significantly (p < 0.05) decreased in LFD, HFC, HFD30, and HFD40 groups compared to LFC and HFD50 groups. One animal died and other animals of the HFD50 group were in a critical condition. Serum lipid and liver glycogen were increased in HFD groups compared to other groups. The results of this study suggest that the HF diet-fed, 40-mg/kg BW STZ-injected SD rat is better than the LF diet-fed NA-STZ-injected rat as an animal model of human type 2 diabetes.