Alteration in cardiac uncoupling proteins and eNOS gene expression following high-intensity interval training in favor of increasing mechanical efficiency

Objective(s):High-intensity interval training (HIIT) increases energy expenditure and mechanical energy efficiency. Although both uncoupling proteins (UCPs) and endothelial nitric oxide synthase (eNOS) affect the mechanical efficiency and antioxidant capacity, their effects are inverse. The aim of this study was to determine whether the alterations of cardiac UCP۲, UCP۳, and eNOS mRNA expression following HIIT are in favor of increased mechanical efficiency or decreased oxidative stress. Materials and Methods: Wistar rats were divided into five groups: control group (n=۱۲), HIIT for an acute bout (AT۱), short term HIIT for ۳ and ۵ sessions (ST۳ and ST۵), long-term training for ۸ weeks (LT) (۶ in each group). The rats of the training groups were made to run on a treadmill for ۶۰ min in three stages: ۶ min running for warm-up, ۷ intervals of ۷ min running on treadmill with a slope of ۵° to ۲۰° (۴ min with an intensity of ۸۰-۱۱۰% VO۲max and ۳ min at ۵۰-۶۰% VO۲max), and ۵-min running for cool-down. The control group did not participate in any exercise program. Rats were sacrificed and the hearts were extracted to analyze the levels of UCP۲, UCP۳ and eNOS mRNA by RT-PCR. Results:UCP۳ expression was increased significantly following an acute training bout. Repeated HIIT for ۸ weeks resulted in a significant decrease in UCPs mRNA and a significant increase in eNOS expression in cardiac muscle. Conclusion:This study indicates that Long term HIIT through decreasing UCPs mRNA and increasing eNOS mRNA expression may enhance energy efficiency and physical performance.

کلیدواژه ها:

eNOS ، High-intensity interval training ، UCP۲ ، UCP۳