Effect Of Aerobic Exercise On PKB Expression In Adipose Tissue Of Insulin Resistant Rats Induced By High Fat Diets

Objective: To develop a rat model of insulin resistance by high fat diets, and to study the effect of aerobic exercise on the expression of protein kinase B in adipose tissue of insulin resistant rats, we tried to explore the mechanism that exercise improves insulin resistance.Methods: 30 male Wistar rats were randomly divided into the control group (n=10), given basic diets; the model group (n=20), given fat-rich-diets. After 4 weeks, the model group was randomly divided into 2 subgroups accepted different interventions of 6 weeks. ①Pathology control group was continually given high fat diets; ②Exercise group accepted high fat food and swimming training. Body weight, fasting plasma glucose, insulin, triglyceride and cholesterol were observed during the experiment. As swimming training ended, all the rats were killed and visceral fat was collected to use. Then the protein expression of PKB in adipose tissue was determined with Western blotting and analysed by computer image system.Results: (1) The model group showed hyperglycemia, hyperinsulinism, hypertriglyceride, and hypercholesterolemia while the insulin resistance index (ISI) was obviously reduced compared to the normal control group, indicating that the insulin resistant model was induced in the way; (2) After 6 week-interventions, exercise training obviously decreased epididymal fat pad weight, fasting blood glucose, triglyceride and cholesterol which accompanied elevated ISI. Plasma insulin was lower, but it did not show any statistical differences between exercise group and pathology control group; (3) Because of long term high fat diets, PKB expression in adipose tissue in the pathology group decreased by 23.5% compared with the normal control group[OD: (0.70±0.13) vs (0.94±0.10), P<0.01]. However, for 6 week-treatments of swimming training, PKB expression in exercise group significantly increased by 19.2% when compared to the pathology group[OD: (0.85 ± 0.05) vs (0.70 ± 0.13), P<0.01].Conclusions: The rats fed with continuous high fat diets can develop insulin resistance mode. When insulin resistance occurs, expression of PKB was significantly reduced in adipose tissue. However, aerobic exercise can promotes PKB expression in adipose tissue, rescue the defect of insulin signal transduction, and ameliorate the state of insulin resistance.