The major finding of this study is that T2D rats (HFD) had a smaller CSA, less intramuscular Pax7 and MyoD gene expression, myostatin and MyoD protein expression, and a lower number of quiescent SC (Pax7+/MyoD−) compared to non-T2D rats (CON) in the soleus muscles. Here, MSTN is linked to type 2 diabetes mellitus.