Effect of Eight Weeks of Resistance Training on PAX۷ and MyoD in Fast and Slow-Twitch Skeletal Muscles of Old Rats

Background: Box ۷ protein (PAX۷) and myogenic differentiation (MyoD) proteins are the essential proteins to regulate the satellite cell and muscle hypertrophy.Objectives: We aimed to investigate the effect of resistance training (RT) on PAX۷ and MyoD in soleus and extensor digitorum longus (EDL) muscles of old rats.Methods: In this experimental study, ۱۲ old female rats were randomly divided into two groups including RT and control groups. The RT program was three days a week for eight weeks, in which the rats climbed a one-meter vertical ladder with ۲۶ steps. The carried weights varied from ۵۰% of body weight in the first week to ۱۰۰% of body weight in the ۸th week. Kolmogorov- Smirnov test and independent sample t test was used for statistical analysis (P≤۰.۰۵).Results: MyoD protein in RT group significantly increased in soleus and EDL muscles compared with the control group (P = ۰.۰۰۱). Also, Pax۷ significantly increased in the soleus muscle in the RT group compared with control group (P = ۰.۰۰۲); nevertheless, there was no significant difference in Pax۷ protein in the EDL muscle between the RT and control groups (P = ۰.۱۰).Conclusion: RT can lead to proliferation and renewal of satellite cells in the soleus and EDL muscles by increasing PAX۷ and MyoD proteins.

Keywords:

Aging , Box ۷ protein , Myogenic differentiation proteins , Exercise , Muscle