High-intensity interval training increases mitochondria biogenesis in adipose tissue and improves insulin resistance in high fat diet-induced obese rat

The purpose of this study was to investigate the effects of high intensity interval training (HIIT) on PGC-1α and mtDNA of subcutaneous adipose tissue and insulin resistance in obese male rats. After inducing obesity with high fat diet(for 10 weeks), eight rats from the high-fat diet group (O) and eight rats of the standard dietary group (C) were sacrificed and other obese rats were randomly divided into two groups: obesity control (OC, n=8) and high intensity interval training (HIIT, n=8). The HIIT protocol includes 10 bouts of 4-minute activity with equivalent intensity of 85-90% vo2max and 2 minute active rest periods for 12 weeks and 5 sessions per week. Western Blot method was used to measure PGC-1α and real time PCR was used to measure. Obesity induced by a high-fat diet resulted in a significant reduction in protein levels of PGC-1α [0.25±0.13 vs. 1] and insignificant reduction in gene expression of mtDNA [0.80±0.02 vs. 1]. In contrast, HIIT resulted in a significant increase in protein levels of PGC-1α [1.64±0.40 vs. 0.29±0.03] and gene expression of mtDNA [4.92±0.59 vs. 0.89±0.02]. In addition to, HIIT resulted in a significant decrease in serum levels of insulin [1.49±0.15 vs. 2.14±0.43 ng/ml] and glucose [111.16±4.07 vs. 154.66±13.21 mg/dl] and improved insulin resistance insulin [1.96±0.20 vs. 3.89±0.54]. It seems likely that HIIT result in increase of adipose tissue mitochondrial biogenesis in obesity which may be involved in improving insulin resistance.