High fat diet-induced obese rats and diabetic rats: a comparative study of glucose and lipid metabolism

Objective To compare the glucose and lipid metabolism between high sucrose plus high fat diet-induced obese rats and diabetic rats prepared with the same feed combined with low-dose streptozotocin.Methods Six to eight weeks old SD rats were randomly divided into normal control group and high fat group,fed with normal diet and high sucrose plus high fat diet for 8 weeks,respectively.Eight weeks later HF group was further randomized into two groups:one is diabetic mellitus group(DM group) injected with low dose streptozotocin(30 mg/kg),the other is obese group(OB group).The animals were maintained on their diet and were observed for 4 weeks.The body weight,blood glucose,triglyceride,total cholesterol,fasting insulin,insulin sensitivity were examined.Intraperitoneal glucose tolerance test(IPGTT) and insulin release test were also performed.Results After treatment with high fat diet plus STZ injection,DM group gradually developed symptoms of excessive food water consumption,polyuria and weight loss.At the end of the 12th week,the fasting blood glucose of DM group was significantly higher than that of the OB group(P 0.01) and the insulin sensitivity was significantly lower than that of the OB group(P 0.01).The rats of OB group presented impaired glucose tolerance and impaired insulin secretion,and DM group had more severely impaired glucose tolerance and impaired insulin secretion;and the serum total cholesterol,triglyceride levels in DM group were significantly higher than those in the OB group(P 0.01).Conclusion Continuous high sucrose-high fat diet can induce impaired glucose regulation,insulin secretion dysfunction and lipid metabolism disorders;high fat combined with STZ injection can further aggravate these disorders.