Effect of exercise training on tumor necrosis factor-alpha and adiponectin expressions in insulin resistance rats

Objective To investigate the effects of exercise training intervention on the expressions of TNF-α and adiponectin in circulation and tissues of high-fat/high-sucrose diet-induced insulin resistance rats. Methods 29 S-D rats were random divided into 2 groups: Control group (9 rats) and high-fat/high-sucrose diet group (20 rats). After fed for 6 weeks, 18 rats with insulin resistance were random divided into 2 groups: model group ( n = 9) and exercise group ( n = 9). After 6 weeks intervention, serum TNF-α and adiponectin concentration were measured by radioimmunity assay and ELISA respectively, while TNF-α and adiponectin mRNA expressions in liver and skeletal muscle were measured by RT-PCR. Results Fasting plasma glucose(FPG) and fasting serum insulin(FINS) levels increased significantly and insulin sensitivity index(ISI) decreased significantly in rats of model group than those in control group(7.49 ± 1.13 vs 5.06±0.38, 33.57 ±4.87 vs 13.61±2.94, -5.51±0.16 vs -4.21 ±0.22, all P <0.05). Serum TNF-α concentration was significantly higher than those in control group, while serum adiponectin concentration was significantly lower. (3.03 ± 0. 50 vs 2. 39 ± 0. 44, 0. 77 ± 0. 09 vs 0. 86 ± 0. 08, all P < 0. 05 ).Expressions of TNF-α mRNA in liver and skeletal muscle increased significantly and adiponectin mRNA expression significantly decreased in rats of model group compared to those in control group (0. 66 ± 0. 19 vs 0. 05 ± 0. 03, 1.15 ± 0. 20 vs 0. 25 ± 0. 10, 0. 25 ± 0. 10 vs 0. 85 ± 0. 13, all P < 0. 01 ). Fasting plasma glucose(FPG) and fasting serum insulin(FINS) levels decreased significantly and insulin sensitivity index (ISI) increased significantly in rats of exercise group than those in model group(5.77 ± 1.17 vs 7.49 ±1.13, 25.69 ±4.27 vs 33.57 ±4. 87, -5. 10 ±0.31 vs -5.51 ±0. 16, all P <0.05) ;Serum TNF-α concentration was significantly lower and serum adiponectin concentration was significantly higher in rats of exercise group than those in model group ( 2.40 ± 0. 59 vs 3.03 ± 0. 50, 0. 86 ± 0. 10 vs 0. 77 ± 0. 09, all P < 0. 05); Expressions of TNF-α mRNA in liver and skeletal muscle decreased significantly and adiponectin mRNA expression increased significantly in rats of exercise group compared to those in model group (0. 21±0. 10 vs 0.66±0. 19, 0.49 ±0. 17 vs 1.15 ±0.20, 0.97 ±0.20 vs 0. 25 ±0. 10, all P <0.01). Conclusion Exercise training can significantly improve insulin resistance, which may be through modulating the expressions of TNF-α and adiponectin. Key words: Exercise;  Insulin resistance;  Tumor necrosis factor-alpha/ME;  Adiponectin/ME