Effects Of Sprint Interval Training On Apoptosis And MHC Gene Expression In Rat Skeletal Muscles

Abstract

Physical exercise induces signaling pathways and regulatory molecules. It is believed that exercise can induce apoptosis which play important roles in retain of tissue and cellular homeostasis. FOXO1 has an important role to regulate apoptosis and induce fiber type transition in skeletal muscle. The effect of sprint interval training on apoptosis and fiber type transitions is unclear. PURPOSE: we examined response of FOXO1 as an important factor of apoptosis and fiber type transition in rat skeletal muscle after acute and chronic sprint interval exercise. METHODS: 24 male Sprague–Dawley rats (200–230 g) divided into 3 groups (n=8); chronic sprint interval (CSI), acute sprint interval (ASI), control (C). CSI was sprinting 1 min and 2–5 min rest between sets (6–10 sets/days, 5–6 days/weeks) on treadmill for 9 weeks. ASI was running with 10 m/min to 85 m/min which gradually increased in 3 consecutive days that included 7 sets of 1 min with rest interval of 3 min in between. Soleus and super vastus lateralis (SVL) muscles mRNA were analyzed by real-time RT-PCR. RESULTS: In soleus muscle, FoxO1 mRNA expression levels had a 1% decrease in ASI and 41% in CSI group compare to control group. In SVL muscle, FoxO1 mRNA expression had a 2% increase in ASI and a 37% decrease in CSI. No significant change in FOXO1 mRNA expression were observed between groups. Also, MHC I and IIa mRNA expression (0.3-, 0.4-fold) in soleus and MHC IIb (0.31-fold) in SVL decreased in CSI group, but in ASI, MHC I mRNA increased (3.69-fold) in SVL significantly (P≤0.05). CONCLUSION: FOXO1mRNA expression is more abundantly in fast muscle and probably has a limited effects on apoptosis in response to sprint interval training.