The effects of different training modalities on monocarboxylate transporters MCT1 and MCT4, hypoxia inducible factor-1α (HIF-1α), and PGC-1α gene expression in rat skeletal muscles

The research literature suggests that different training modalities cause various patterns in training-induced genes expression. This study aimed to investigate the effects of moderate intensity continuous training (MICT) and isocaloric high intensity interval training (HIIT) on gene expression of monocarboxylate transporter 1 (MCT1) and 4 (MCT4), Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1 alpha), and hypoxia inducible factor-1 alpha (HIF-1 alpha) in soleus and extensor digitorum longus (EDL) skeletal muscles of rats. Thirty male Sprague-Dawley rats were divided into 3 groups of control, MICT, and HIIT. Training protocols were performed according to the principle of overload for 8 weeks and 5 sessions per week. Then, the soleus and EDL muscles were extracted and the expression levels were analyzed using the real time PCR method. In the MICT group, only the EDL HIF-1 alpha mRNA level was significantly higher than that of the control group (p < 0.05). In the HIIT group, however, mRNA levels of MCT4, PGC-1 alpha, and HIF-1 alpha in both muscles were significantly higher than those of the control group (p < 0.05). The comparison between the two training methods demonstrated that the gene expression levels of soleus and EDL MCT4, soleus PGC-1 alpha, and soleus HIF-1 alpha were significantly higher in the HIIT group compared to the MICT group (p < 0.05). There were also significant positive correlations between all mRNA levels of HIF-1 alpha and corresponding mRNA levels of MCT4 (p < 0.05). HIIT caused greater positive responses in the gene expression of MCT4, PGC-1 alpha, and HIF-1 alpha compared to MICT.