Tang H.,Hunan University of Science and Technology |
Xie M.-H.,Beijing University of Sports |
Lei Y.,Tongren University |
Zhou L.,Hunan University of Science and Technology |
And 2 more authors.
Cytokine | Year: 2013
Objective: To demonstrate the hypothesis that aerobic exercise training inhibits the development of insulin resistance through IL-6 and probe into the possible molecular mechanism about it. Methods: Rats were raised with high-fat diets for 8. weeks to develop insulin resistance, and glucose infusion rates (GIRs) were determined by hyperinsulinemic-euglycemic clamping to confirm the development of insulin resistance. Aerobic exercise training (the speed and duration time in the first week were respectively 16. m/min and 50. min, and speed increased 1. m/min and duration time increased 5. min every week following it) and/or IL-6shRNA plasmid injection (rats received IL-6shRNA injection via the tail vein every two weeks) were adopted during the development of insulin resistance. The serum IL-6, leptin, adiponectin, fasting blood glucose, fasting serum insulin, GIR, IL-6 gene expression levels, p-p38 in various tissues and p-STAT3/t-STAT3 ratio in the liver were measured. Results: Rats fed with high-fat diets for 8. weeks were developed insulin resistance and the IL-6mRNA levels of IL-6shRNA injection groups in various tissues were significantly lower than those of control group (P< 0.05), respectively. The development of insulin resistance in exercise rats significantly decreased, however, compared with that, the GIR of exercise rats injected by IL-6shRNA was lower (P< 0.05). The IL-6mRNA levels were highest in the fat tissue and lowest in the skeletal muscles in all the rats. The serum adiponectin levels decreased (P< 0.05) following the development of insulin resistance, and it increased (P< 0.05) when the rats were intervened by aerobic exercise training for 8. weeks at the same time. However, there were not significant differences when serum leptin concentrations were compared (P> 0.05). The p-p38 significantly increased in the rats fed with high-fat diets, however, p-p38 of the exercise high-fat diets rats in the liver and fat tissues significantly decreased than that (P< 0.05). The changes of p-p38 in exercise rats injected by IL-6shRNA were irregular. The activation of STAT3 in the liver significantly increased (P< 0.05) following the development of insulin resistance, and it decreased (P< 0.05) when the rats were intervened by aerobic exercise training for 8. weeks at the same time, and the gene silencing of IL-6 did not have effects on the activation of STAT3 in the liver (P> 0.05). Conclusions: In conclusion, aerobic exercise training prevented the development of insulin resistance through IL-6 to a certain degree. The gene expression and secretion of IL-6 could inhibit the development of insulin resistance. The mechanism of the effects were possibly related with elevating the levels of serum adiponectin, and/or inhibiting the activation of STAT3 in the liver and p38MAPK in the skeletal muscles, liver and fat tissues. © 2012 Elsevier Ltd.