Effects of regular-moderate exercise on high-fat diet-induced intramyocellular lipid accumulation in the soleus muscle of Sprague-Dawley rats.

Previously, we monitored the expression level of the pro-apoptotic proteins caspase-3 and cleaved poly-ADP-ribose polymerase in the skeletal muscle of high-fat diet-induced obese rats in order to assess muscle damage. In this study, we analyzed whether exercise or dietary adjustment was more effective at preventing high-fat diet-induced muscle damage. High-fat diet-induced obese rats were divided into three groups: the high-fat diet (HFD), the combined high-fat diet and exercise (HFD+EXE), and the dietary adjustment (DA) groups. For 6 weeks, the HFD+EXE group was subjected to exercise on an animal treadmill. Capsase-3 protein was quantified, and histopathology of the soleus muscle was performed. Both the HFD+EXE and DA interventions resulted in a reduction of lipid accumulation in the soleus muscle, and nucleus infiltration was significantly lower in the DA group. The inflammatory response, caspase-3 level, and relative muscle weight were significantly higher in the HFD+EXE group compared to the HFD group. An increase in intramyocellular lipids in the soleus muscle by obesity and exercise stimulated apoptosis. When the rats exercised, muscle growth was normal and unrelated to the effects of lipid accumulation. These data indicate that exercise was more effective than dietary adjustment in reducing lipid accumulation and increasing muscle metabolism.