Beneficial Mitochondrial Biogenesis in Gastrocnemius Muscle Promoted by High-Intensity Interval Training in Elderly Female Rats

OBJECTIVE: Exercise can attenuate mitochondrial dysfunction caused by aging. Our study aimed to compare 12 weeks of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on the expression of mitochondria proteins [e.g., AMP-activated protein kinase (AMPK), Estrogen-related receptor alpha (ERRα), p38 mitogen-activated protein kinase (P38MAPK), and Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1-α)] in gastrocnemius muscle of old female rats. MATERIALS AND METHODS: In this experimental study, thirty six old female Wistar rats (18-month-old and 270-310 g) were divided into three groups: i. HIIT, ii. MICT, and iii. Control group (C). The HIIT protocol was performed for 12 weeks with 16-28 minutes (2 minutes training with 85-90% VO(2max)in high intensity and 2 minutes training with 45-75% VO(2max) low intensity). The MICT was performed for 30-60 minutes with the intensity of 65-70% VO(2max). The gastrocnemius muscle expression of AMPK, ERRα, P38MAPK, and PGC1α proteins were determined by Western blotting. RESULTS: The expression of AMPK (P=0.004), P38MAPK (P=0.003), PGC-1α (P=0.028), and ERRα (P=0.006) in HIIT was higher than C group. AMPK (P=0.03), P38MAPK (P=0.032), PGC-1α (P=0.015), and ERRα (P=0.028) in MICT was higher than the C group. Also expression of AMPK (P=0.008), P38MAPK (P=0.009), PGC-1α (P=0.020) and ERRα (P=0.014) in MICT was higher than MICT group. CONCLUSION: It seems that exercise training has beneficial effects on mitochondrial biogenesis, but the HIIT training method is more effective than MICT in improving mitochondrial function in aging.