Effects of exercise on the expression of glycogen synthase kinase-3 in the skeletal muscles of insulin resistant rats

Objective To observe the effects of exercise training on the expression of glycogen synthase ki-nase-3 (GSK-3) in the skeletal muscles of rats with insulin resistance induced by a high-fat and high sucrose diet. Methods Thirty Wistar rats were randomly divided into three groups: a control group, a model group and an exercise group. Rats in the model and exercise groups were fed with a high-fat and sucrose diet (20% sucrose, 10% lard, 2.5% cholesterol, 1% cholic acid) for 4 weeks, and then the rats in the exercise group were trained by swimming 5 d every week for 6 weeks. After treatment, the concentration of GSK-3 protein in their muscles was detected by Western blot analysis, while their weights, serum triglyceride and total cholesterol, and their concentrations of fasting plasma glucose and fasting plasma insulin were measured periodically and their insulin sensitivity index was calculated. Results Compared with the controls, the expression of GSK-3 in the skeletal muscles of the rats in the model group increased by 70. 20% (P 0. 01) , while the expression of GSK-3 protein in the exercise group was less by 27.24% (P0.01) than that in the model group. Conclusion The expression of GSK-3 in the skeletal muscles of rats with insulin resistance could be decreased by exercise training, which might ameliorate the insulin resistance by promoting the uptake and utilization of glucose.