Effects of exercise-induced apelin levels on skeletal muscle and their capillarization in type 2 diabetic rats

IntroductionExercise-induced apelin as a myokine is believed to play a role in the improvement of type 2 diabetes mellitus (T2DM) and capillarization. In this study, we evaluated the association between exercise-induced apelin and muscle capillarization. MethodsZucker rats underwent a treadmill exercise program. Body composition, muscle strength, muscle size, muscle capillarization, and insulin resistance (homeostatic model assessment [HOMA-IR]) were measured. Apelin levels of skeletal muscle and plasma were then analyzed. ResultsExercise improved body composition (P<0.05), HOMA-IR (P<0.05), and grip strength (P<0.001). In the soleus, the fiber size of T2DM was decreased (P<0.001), but it increased in fiber size and capillarization after exercise (P<0.001) occurred. We identified an increase in plasma apelin (P<0.05) and a decrease in soleus apelin (P<0.01), as well as an association between soleus apelin and angiogenesis (P<0.01). DiscussionA role for exercise-induced apelin in improving metabolism indicates the possibility of a new drug target for the treatment of metabolic diseases and repairing skeletal muscle damage. Muscle Nerve56: 1155-1163, 2017