Gene Response Of The Gastrocnemius And Soleus Muscles To An Acute Aerobic Run In Rats

Abstract

PURPOSE: Numerous genes can be either activated or inhibited by an acute bout of exercise. It is unclear how two different muscles would respond to the same activity with similar modes of actions. Therefore the purpose of this investigation was to determine the gene response of selected genes involved in the "damage"-response of the gastrocnemius (fast-twitch) and soleus (slow twitch) muscles to a single two hour aerobic exercise bout in female Sprague-Dawley Rats. METHODS: Rats were run (n = 8,) for 2 hours at 20 m/min and one hour after the completion of the bout, all exercisers (E) had their soleus (S) and gastrocnemius (G) muscles removed. Age and timed match sedentary controls (C) also had their muscles removed. RNA was isolated from all muscles. Real-time PCR analysis was performed on the following genes: NFkB, TNFa, and Atf3. GAPDH was used as the housekeeping gene for both muscles. RESULTS: NFkB gene expression was -1.2 ± 0.14 in the ES but was + 1.36 ± 0.58 in the EG. TNFa was altered 1.30 ± 0.34 in the ES and 1.36 ± 0.71 in the EG. The gene Atf3 was positively altered 4.97 ± 1.01 in the ES, while it was only slightly altered in the EG (0.70 ± 0.55). CONCLUSIONS: This study demonstrates that an acute bout of aerobic exercise can alter gene expression to a different extent in both the soleus and gastrocnemius muscles. It is highly likely that recruitment of the muscles may have been a factor which influenced the gene expression in theses muscles. It is interesting to note that some genes were similarly activated in these muscles but other genes may adapt to the same exercise bout in a varied manner.