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


METHODS
Zucker 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.


RESULTS
Exercise 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).


CONCLUSIONS
A 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 Nerve 56: 1155-1163, 2017.
Health and Exercise Science Laboratory, Institute of Sport Science, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.|Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea.
Jun Seok
JS
Son
Health and Exercise Science Laboratory, Institute of Sport Science, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.|Physical Activity & Performance Institute, Konkuk University, Seoul, Republic of Korea.
Hee-Jae
HJ
Kim
Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea.|Laboratory of Development Biology and Genomics, BK21 Program for Veterinary Science, Institute for Veterinary Science, Seoul National University, Seoul, Republic of Korea.
Yeri
Y
Son
Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea.|Laboratory of Development Biology and Genomics, BK21 Program for Veterinary Science, Institute for Veterinary Science, Seoul National University, Seoul, Republic of Korea.
Hojun
H
Lee
Health and Exercise Science Laboratory, Institute of Sport Science, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
Song Ah
SA
Chae
Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea.|Laboratory of Development Biology and Genomics, BK21 Program for Veterinary Science, Institute for Veterinary Science, Seoul National University, Seoul, Republic of Korea.
Je Kyung
JK
Seong
Health and Exercise Science Laboratory, Institute of Sport Science, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.|Korea Mouse Phenotyping Center, Seoul National University, Seoul, Republic of Korea.|Institute on Aging, Seoul National University, Seoul, Republic of Korea.
Wook
W
Song
D000818:Animals; D000073861:Apelin / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002196:Capillaries / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000628:therapy; D005080:Exercise Test / Q000379:methods; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000379:methods / Q000502:physiology*; D051381:Rats; D011924:Rats, Zucker
D000073861:Apelin; C498579:Apln protein, rat; D015415:Biomarkers
exercise; metabolism; muscle capillarization; muscle fiber size; muscle strength; myokine