Effect of dietary restriction with or without exercise training on β-catenin and glycogen synthase kinase-3β gene expression in skeletal muscle of male rats

Dietary restriction and exercise training are practical intervention for weight loss and increasing lifespan. However, the effect of dietary restriction with or without exercise training on muscle mass and strength remain unclear. In addition, signaling process and proteins involved in this field have not been clearly specified. Therefore, the purpose of this study was investigating the effect of dietary restriction with or without exercise training on β-catenin and glycogen synthase kinase-3β gene expression in soleus muscle of male rats. 24 male rats randomly divided into three groups: control (Con), dietary restriction (DR) and dietary restriction+ exercise training (DR+EX). Within three months of research, All animals in Con group were fed ad libitum, while animals of DR and DR+EX group had daily access to 50% of the intake of the ad libitum-fed Con animals. Rats in DR+EX group participated in the exercise training program for 12 weeks. 48 hours after the last training session, the skeletal muscle of rats were extracted and β-catenin and glycogen synthase kinase-3β mRNA evaluated by Real Time-PCR. One-way ANOVA and post-hoc Tukey were applied for statistical analysis of the data (p< 0.05). β-catenin gene expression of DR and DR+EX group was no-significantly lower than the Con group (38% and 8.8% respectively, p˃0.05). However, glycogen synthase kinase-3β gene expression of DR group was significantly higher than the Con and DR+EX group (449% and 177% respectively, p<0.05). Overall, a 12-week dietary restriction (-50%) increased the glycogen synthase kinase-3β gene expression in Wnt-signaling pathway of skeletal muscle. This may be associated with a decreased muscle mass and strength. However, it is likely that the addition of exercise training to dietary restriction alleviates loss of skeletal muscle.