The effect of eight weeks of aerobic exercise with moderate and high intensities on serum irisin and PGC-۱α protein levels in obese male Wistar rats

Background and aims: Irisin myokine whose secretion is induced by exercise is associated with an increase in thermogenesis. However,the effect of aerobic exercise with different intensities on the production and release of irisin in overweight individuals is controversial.This study aimed to investigate the effect of eight weeks of aerobic training with different intensities on PGC-۱α, FNDC۵, UCP۱, and irisinin obese male Wistar rats.Methods: In this experimental study, ۲۴ adult obese male Wistar rats (weight: ۲۵۰-۳۰۰ g; body mass index [BMI] >۳۰ g/cm۲) divided intothree groups, including aerobic training with ۲۸ m/min (moderate intensity [MI]), aerobic training with ۳۴ m/min (high intensity [HI]), andcontrol. All training groups exercised for eight weeks walking on a treadmill (five ۶۰-min sessions per week). The paired sample t test andone-way ANOVA were used to determine the intra- and inter-group differences. Furthermore, Tukey’s post hoc test was used.Results: The levels of PGC-۱α in muscle tissue in aerobic training groups with MI and HI increased (P = ۰.۰۰۱ and F = ۱۱.۸۱) compared tocontrol group. The levels of irisin (P = ۰.۰۰۶ and F = ۶.۱۰) and UCP۱ (P = ۰.۰۴) were significantly increased in MI group. On the other hand,FNDC۵ increased significantly in both MI and HI groups (P = ۰.۰۰۱ and F = ۱۲.۴۹). While irisin and UCP۱ levels increased in HI groupcompared to the control group, the change was not statistically significant (P > ۰.۰۵). The levels of irisin, UCP۱, and FNDC۵ increased moresignificantly in MI group than in HI group (P < ۰.۰۵).Conclusion: Both types of aerobic training (MI and HI) had a beneficial effect on changes in irisin, UCP۱, FNDC۵, and PGC-۱α levels.Accordingly, moderate exercise possibly changes the phenotype of white to brown adipose tissue leading to an increase in thermogenesis,body weight loss, and sensitivity to insulin.