Effect of diet intervention on expression of protein kinase B in liver tissue of insulin-resistant rats fed a high-fat diet

Objectives To study the effect of diet intervention on expression of protein kinase B(PKB) in liver tissue of insulin-resistant rats fed a high-fat diet.Methods Thirty male Wistar rats were randomly divided into control group(n=10) which were given a low-fat diet and model group(n=20) which were given a fat-rich diet.After 5 weeks,model group was randomly divided into 2 subgroups to accept diet intervention for 6 weeks:10 rats in high-fat diet group were continually given a fat-rich diet and 10 in low-fat diet group accepted a low-fat diet.Expression of PKB stimulated by insulin in rat-liver tissue was examined using Western blotting at the end of the experiment.Results(1) After 5 weeks,rats in model group showed hyperglycemia,hyperinsulinism,hypertriglyceride,hypercholesterolemia and a significant increase in homeostasis model assessment-insulin resistance index(HOMA-IR) while insulin resistance index(ISI) was obviously reduced compared to those in control group,indicating that the insulin resistant model was successfully induced.The difference between the 2 groups was of statistical significance(P0.01).(2) The 6-week low-fat diet treatment decreased fasting blood glucose,triglyceride and cholesterol of the rats,accompanied by lower HOMA-IR and higher ISI compared with those in high-fat diet group.The difference between the 2 groups was also of statistical significance(P0.05).(3) Expression of PKB in rat-liver tissue from high-fat diet group decreased by 23.5% which was much lower than that from control group.The difference was of statistical significance(7.34±0.19 vs.8.97±0.20,t=9.335,P0.001).After 6 weeks;diet intervention,there was a 4.9% increase in PKB expression from low-fat diet group compared with that from high-fat diet group.The differece was of statistical singnificance(7.70±0.18 vs.7.34±0.19,t=10.102,P0.001).Conclusions Insulin resistance can be induced by a long-term high-fat diet.Diet intervention can correct diabetic dyslipidemia and ameliorate insulin resistance,which may be relative to the increase of PKB expression in liver tissue.