The Effect of Long-Term Endurance Activity on purβ Gene Expression in Rat Fast and Slow Twitch Skeletal Muscles

Increased expression of type I fibers due to endurance activity, is inhibited by "purine-rich element binding protein A" transcription factor. The purpose of the present study was to investigate the effect of one period of endurance activity on the gene expression of this factor in fast and slow twitch skeletal muscles.
In this experimental study, 20 male Wistar rats (age, 5 weeks and weight, 113±20g), were randomly divided into two groups of experimental and control. A 14-week endurance activity program on motorized treadmill, was designed for the experimental group on the treadmill, then 48 hours after the end of the last training session, the rats were anesthetized and dissected. Then, the soleus and extensor digitorum Longus muscles, were removed. The expression level of "purine-rich element binding protein A" in these muscles, were measured using real time PCR method. Data were analyzed using t-test.
In this study, endurance activity significantly decreased (p≤0.01) the expression level of "purine-rich element binding protein A" gene in fast twitch muscle (extensor digitorum longus) and significantly increased the expression of this gene in slow twitch muscle (soleus muscle).
The result of this research revealed that despite the same endurance activity, purβ gene expression in fast and slow twitch muscles, is different. This is probably due to the upstream signaling cascade of this gene, which controls its expression level.