The Effect Of Different Intensity Exercise On The Insulin Signal Transduction Pathway Of TCDD Exposed SD Rats

Objective: In this study,SD rats were used as experimental subjects to investigate the effect of different intensity exercise on insulin signal transduction pathway under2,3,7,8-TCDD exposed,then to analyze whether exercise can alleviate its pathway and glucose metabolism toxicity.Methods: After one week of adaptive exercise,sixty male SD rats(7 weeks old)were divided into 6 groups according to their body weight,respectively non-exercise control group(NC),none exercise toxic group(NT),moderate-intensity exercise control group(MIT),moderate-intensity exercise toxic group(MIT+T),high-intensity exercise control group(HIT),high-intensity exercise toxic group(HIT+T).NT,MIT+T,HIT+T groups were received first 2,3,7,8-TCDD intra peritoneal injection dose respectively of 6.4μg/kg·bw,then received 21% of the initial dose exposure for the next7 weeks.NC,MIT,HIT groups were received same quantity of corn oil.The exercise program of MIT and MIT+T groups was slope 5%,15m/min,60min/ day,equivalent to 60%VO2max intensity.The exercise program of HIT and HIT+T groups was slope5%,26m/min,35min/ day,equivalent to 75%VO2max intensity.At the end of the experiment,all rats were killed and tested the body weight.The concentration of blood glucose,insulin and C-peptide were detected,then the HOMA-IR index was calculated according to the formula.The rat liver was extracted to detect the contents of PI3 Km RNA,AKTm RNA,IRS2 m RNA,PI3 K,AKT,IRS2 and the phosphorylation levels of AKT(Thr308),IRS2(Ser 731).Results: Moderate-intensity exercise have main effect on concentration of glucose(P=0.012);TCDD exposure(P=0.026)and moderate-intensity exercise(P=0.022)have main effect on concentration of insulin;moderate-intensity exercise have main effect on concentration of C-peptide(P=0.010);TCDD exposure(P=0.049),moderateintensity exercise(P=0.001)and high-intensity exercise(P=0.010)all have main effect on HOMA-IR index,moderate-intensity exercise and TCDD exposure have interaction effect on HOMA-IR index(P=0.029);TCDD exposure have main effect on IRS2 m RNA(P=0.033),high-intensity exercise and TCDD exposure have interaction effect on IRS2 m RNA(P=0.016);TCDD exposure(P=0.002),moderate-intensity exercise(P=0.035)and high-intensity exercise(P=0.005)all have main effect on the content of PI3K;TCDD exposure have main effect on the content of AKT(P=0.002),highintensity exercise and TCDD exposure have interaction effect on the content of AKT(P=0.008);TCDD exposure(P=0.001)and moderate-intensity exercise(P=0.021)have main effect on the phosphorylation level of AKT(Thr308),high-intensity exercise and TCDD exposure have interaction effect on the phosphorylation level of AKT(Thr308)(P=0.005);TCDD exposure have main effect on the content of IRS2(P=0.030);TCDD exposure have main effect on the phosphorylation level of IRS2(Ser731)(P=0.001),moderate-intensity exercise have main effect on the phosphorylation level of IRS2(Ser731)(P=0.0241).Conclusion: 1.TCDD can disrupt the insulin signal transduction pathway in the liver of rats,decrease insulin sensitivity and develop insulin resistance.2.Exercise can improve insulin sensitivity and promote the activation of insulin signal transduction pathway,and the promoting effect of moderate intensity exercise is more obvious than high-intensity exercise.3.Moderate intensity exercise can effectively alleviate insulin resistance of rats induced by TCDD,whereas high-intensity exercise can’t alleviate it obviously and may even aggravate the disorder of its signal transduction pathway.