Increased Expression of miR-1 in Fast-Twitch Skeletal Muscle in Response to Resistance Exercise

Abstract

Background: The response of microRNA (miR-1), upstream regulators (Myogenic Differentiation 1 (MyoD1) and Myocyte Enhancer Factor 2C (Mef2C)), and a downstream target (Histone Deacetylase 4 (Hdac4)) to an acute bout of Resistance Exercise (RE) in Extensor Digitorum Longus (EDL) and soleus muscles has remained elusive. Objectives: In this experimental study, we investigated the effect of an acute bout of RE on the expression of miR-1, MyoD1, Mef2C, and Hdac4 genes in the slow and fast-twitch muscle of rats. Methods: The current study was conducted at Tarbiat Modares University, Tehran, Iran, in 2017. Fifteen male Wistar rats were randomly divided into two groups, control (n = 5) and RE (n = 10). The RE protocol consisted of four sets of five repetitions of climbing a ladder with weights attached to the tails of rats. The soleus and EDL muscles of rats were collected at 3 h (n = 5) and 6 h (n = 5) post-RE. The real-time polymerase chain reaction was used to measure the levels of miR-1, MyoD1, Mef2C, and Hdac4 mRNA expression. Results: The miR-1 expression in EDL muscle was significantly lower at 3 h and 6 h post-exercise in the RE group than in the control group (P < 0.01). The miR-1 expression in soleus muscle was significantly lower at 3 h post-exercise in the RE group than in the control group (P < 0.007) but it was significantly higher at 6 h post-exercise (P < 0.036). The expression of MyoD1, Mef2C, and Hdac4 genes in the EDL muscle was higher in the RE group than in the control group (P < 0.01). The expression of these genes in response to RE had more fluctuations in soleus muscle. Conclusions: It can be concluded that miR-1 expression in extensor digitorum longus and soleus muscles of rats responds to resistance exercise in different manners and this coincides with a change in upstream regulators and downstream target.