The Effect of High-Intensity Interval Training on Mitochondria Fission-Related Factors in Skeletal Muscle of Old Wistar Rats

Healthy mitochondrial dynamics are controlled by a regulated balance between mitochondrial fusion and fission. An imbalance between the fusion and fission processes in skeletal muscle mitochondria has been reported by aging (۲). The mitochondrial fission is regulated by dynamin-related protein ۱ (Drp۱) and fission protein ۱ (Fis۱) (۱).Exercise has been considered as an effective strategy to protect against aging-related complications such as sarcopenia. Few studies have shown changes in both fusion and fission-related factors in aging skeletal muscle following endurance training (۳). However, the effect of High-Intensity Interval Training (HIIT) on fission factors has not been well elucidated in aging.Therefore, the purpose of this study was to research the effect of HIIT on Drp۱ and Fis۱ gene expression in skeletal muscle of old rats.Eight young male Wistar rats with the age of eight to ten weeks and the mean of ۳۲۰ g in weight, and also ۱۶ old rats with ۱۶ to ۱۸ months of age and mean of ۴۵۰ g in weight were provided for the research. Young rats were considered as Young-Control (n=۸). The old rats were divided into Old-sedentary (n=۸) and Old-Training (n=۸). The training group was subjected to exercise training on a treadmill with ۱۰° inclination for eight weeks (۵ days per week). Rats were exercise-trained by six interval occasions so that they ran at ۹۰% vVo۲peak for ۳-minutes followed by a ۲-minute active recovery at ۵۰% vVo۲peak for ۲-minutes. The gene expression of Drp۱ and Fis۱ in the Soleus muscle was determined by Real-Time PCR.Data showed a higher level in Fis۱ gene expression in the Old-Sedentary group as compared to the Young-Control group (۳.۴-fold; P=۰.۰۰۱). However, Drp۱ gene expression was not significantly higher in Old-Sedentary than Young-Control (۱.۳-fold; P=۰.۰۹). Moreover, the expressions of Drp۱ and Fis۱ were not significantly lower in the Old-Training group as compared to the Old-Sedentary group (P>۰.۰۵).The results imply that the expression levels of the mitochondrial fission-related factor, i.e. Fis۱ are increased by aging. However, exercise training as HIIT could not effectively decrease the elevated levels of Fis۱ in old rats.

کلیدواژه ها:

Mitochondria Fission ، High-Intensity Interval Training ، Dynamin-related protein ۱ ، Fission protein ۱ ، aging