Abstract: Objective To establish a fast and convinient type 2 diabetes mellitus (T2DM) rat model. Methods Six-week-old male SD rats were randomly allocated into three groups: normal control group, egg-diet group and model group. The model rats were injected intraperitoneally with 30 mg/kg streptozotocin (STZ), then fed egg-diet for 4 weeks to induce diabetes. NC group rats were fed normal chow diet for 4 weeks. Egg-diet group rats were fed egg-diet for 4 weeks. Islet function in each group was evaluated by oral glucose tolerance test (OGTT). 24hr urine specimen was collected and used to analyze urinary albumin and creatinine content. The serum biochemical indices such as FBG, FIns, TG, TC, FFA, SOD, MDA levels were measured. Islets were examined with immunohistochemical analysis of insulin. Kidneys were evalutated with HE staining and transmission electron microscopy respectively. Results Compared with NC rats, the body weight in model group and egg-diet group was increased markedly. Levels of FBG, FIns, TG, TC, MDA in model groups were increased significantly, while SOD levels and ISI values were decreased significantly. 24hr urine excretion, urine albumin and creatinine level in model group were all increased markedly. The pancreatic islets appeared smaller significantly in model group than in NC group. The kidneys in model rats became hypertrophic and kidney indices were increased significantly than in NC rats. Pathological examination showed that basilar membrane in model rats became asymmetrical thicken, foot protrusions became widen and fused mutually. Conclusions This method for improving T2DM rat model was high-efficient, stable and had low death rate, suitable for studying the mechanism and therapy of type 2 diabete mellitus and its chronic complications especially diabetic nephropathy.

Key words: Type 2 diabetes mellitus, SD rats, Streptozotocin, Egg diet, Insulin resistance