The effects of aerobic exercise on ERK1/2 activity in skeletal muscle of type 2 diabetic rats

Abstract

To observe the effects of aerobic exercise on activity of extracellular signal-regulated kinase (ERK1/2) in skeletal muscle of type 2 diabetic rats and explore the prevention and control mechanism of aerobic exercise on type 2 diabetes. Seventy five SD rats were randomly divided into:normal control group(CON) including 15 rats was fed with normal diet, diabetes control group 1(DC1), diabetes exercise group 1(DE1), diabetes control group 2(DC2), diabetes exercise group 2(DE2). Diabetes model group were fed with high-fatty and high-sugar diet. The diabetes model rats were fed with high-fatty and high-sugar diet for 8 weeks,.Diabetes group 2 rats were injected intraperitoneal streptozotocin(STZ)to induce type 2 diabetes. At the early stage of last swimming week, diabetes exercise group1 and diabetes control group 1 were injected with STZ (35 mg/kg) at the same time, After three days, if the level of blood glucose was ≥ 16.7mmol/L, the model was successful. After 8 week-interventions, all the rats were killed, the serum levels of insulin and the expression of ERK1/2 protein in skeletal muscle were determined. ①Compared with the normal control group, the levels of total cholesterol(TC), triglyceride(TG), low density lipoprotein cholesterin(LDL-C), free fatty acid(FFA), fasting blood-glucose(FBG), fasting insulin(FIN) and insulin resistance index(HOMA-IR) were increased significantly in diabetes control group(P<0.05 or 0.01). However, the expression of ERK1/2 phosphorylation protein was decreased obviously in diabetes control group. The content of ERK1/2 protein was decreased obviously in diabetes control group 2 had (P<0.05). 2.After eight weeks' swimming, compared with the diabetes control group, the levels of TC,TG, FFA, LDL-C, FBG, FIN and HOMA-IR were decreased significantly in diabetes exercise group(P<0.05 or 0.01). At the same time, the expression of ERK1/2 phosphorylation protein was increased obviously in diabetes exercise group(P<0.05). Long-term aerobic exercise can improve the skeletal muscle ERK1/2 phosphorylation and insulin resistance of type 2 diabetic rats, thereby lowering blood glucose. It is probably one of the mechanisms to improve glucose metabolism disorders and insulin sensitivity.