An Investigation of the Effect of Upper Limb Resistance Training after Lower Limb Immobilization on FoxO3a, MuRF1 and MAFbx Gene Expressions of Soleus Muscle in Trained Rats

Inactivity can ultimately lead to obesity and activation of the proteolysis messenger pathways, which decreases muscle mass and skeletal muscle contractile power. The aim of this study was to investigate the effect of resistance training during the period of muscular inactivity on the expressions of atrophy processes regulatory genes of soleus muscle in the trained rats. 18 male Sprague Dawley rats were divided into two groups: control (n = 6) and endurance training (n = 12). Endurance training rats ran on a treadmill for 6 weeks and 5 sessions per week. Then, their lower limbs were immobilized for 7 days by plaster cast method and they were divided into two groups: immobilization (n = 6) and resistance training (n = 6). Resistance training and immobilization groups performed 3 sessions of resistance training of ladder climbing with hands in 3 sets, 5 repetitions each set. At the end of 7 days of immobilization, soleus muscle was excised and gene expressions (FoxO3a, MuRF1 and MAFbx) were measured by Real Time-PCR. One-way ANOVA test was used to determine the differences and Tukey post hoc test was used to determine the significance level among the groups (P≤0.05). The results showed that resistance training significantly reduced FoxO3a (P=0.001), MuRF1 (P=0.013), MAFbx (P=0.008) compared with endurance immobilization group. Resistance training seems to prevent muscle atrophy in the immobilization period through reducing or not increasing gene expressions of FOXO, MuRF1, and MAFbx.  Resistance training is likely to be a suitable solution to reduce muscle atrophy caused by muscle immobility.