Effect of treadmill exercise on skeletal muscle autophagy in rats with obesity induced by a high-fat diet

Treadmill exercise induced improvements in body weight, body fat, and biochemical indicators of obesity and Type 2 diabetes, but had no effect on autophagy in soleus muscle.

Triglyceride, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, insulin, and glucose levels were measured, the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) score was calculated, and the soleus muscle was analyzed for autophagy-related factors (Beclin-1, p62, LC3, Lamp-2) in rats with obesity induced by a high-fat diet. Eight-week-old Sprague Dawley rats were fed a high-fat diet for 35 weeks and then subjected to 10 weeks of treadmill exercise. The experimental group was divided into a Normal Diet-Sedentary (ND-SED, n=8) group, an (High-Fat Diet-Sedentary (HF-SED, n=8) group, and an High-Fat Diet + Treadmill Exercise (HF-TE, n=8) group. The intensity of treadmill exercise was set as 8 m/min for 5 min, 11 m/min for 5 min, 15 m/min for 20 min, and 11 m/min for the last 5 minutes. A glucose tolerance test was performed at the 2nd and 8th week of exercise by sampling of tail blood.

This study aimed to investigate the effects of treadmill exercise on body weight, blood biochemistry, and autophagy.

With endurance exercise, the HFTE group showed a significant decrease in body weight, with improved blood biochemical indices and HOMA-IR scores, in comparison with the HF-SED group. However, there was no significant difference in Beclin-1, p62, LC3, and Lamp-2 proteins as measured by autophagic flux in the soleus muscle.