[Effects of acute and chronic exercise on fat PI3K/AKT/GLUT4 signal pathway in type 2 diabetic rats]

To study the effects of acute and chronic exercise on phosphatidylinositol 3-hydroxy kinase(PI3K)/protein kinase B(AKT)/glucose transporter 4(GLUT4)signaling pathway in adipose tissue of rats with type 2 diabetes mellitus (T2DM) induced by high-fat diet and low-dose streptozotocin (STZ).

A total of 52 SD male rats aged 15 months were randomly divided into normal control group (13) and high-fat group (39), and fed normal and high fat diets. After 8 weeks, the body weight of the high-fat group was higher 20% than that of the normal control group. After a small dose of STZ, the blood glucose level was ＞16.7 mmol/l, and the model was successfully established. The diabetic model group was randomly divided into a diabetic control group (DC, n=13), a diabetic chronic exercise group (DCE, n=13), and a diabetic acute exercise group (DAE, n=13). The DCE group underwent an 8-week swimming exercise and the DAE group performed a one-time swimming exercise. Blood lipids, blood glucose and serum insulin levels were measured, and the contents of fat PI3K, AKT and GLUT4 proteins were determined by Western blot method.

The levels of body weight, blood lipids, blood glucose and insulin in the diabetic group were significantly higher than those in the normal control group (P＜0.01); high density liptein cholesterol(HDL-C) levels were decreased (P＜0.05), and the expressions of PI3K, AKT and GLUT4 protein in adipose tissue were decreased (P＜0.01). After 8 weeks of swimming training, the levels of body weight, blood lipids, blood glucose and insulin all were decreased significantly (P＜0.01); while the level of HDL-C was increased (P＜0.05), and the expressions of PI3K, AKT and GLUT4 protein were increased (P＜0.01). After acute exercise, the levels of blood lipids, blood glucose and insulin were decreased (P＜0.05); the level of HDL-C was increased (P＜0.05), and the expression levels of fat PI3K, AKT and GLUT4 were increased significantly (P＜0.05).

①High fat diet combined with low-dose STZ induced damage to the PI3K/AKT pathway in adipose tissue of T2DM rats reduced insulin sensitivity. ②Acute and chronic aerobic exercise can improve the disorder of glucose and lipid metabolism through PI3K/AKT pathway, and the chronic exercise is better than acute exercise.