L-arginine supplementation causes additional effects on exercise-induced angiogenesis and VEGF expression in the heart and hind-leg muscles of middle-aged rats.
The effects of dietary L-arginine supplementation on exercise-induced angiogenesis and VEGF expression were examined in male middle-aged (12 months old) Wistar rats. Exercise training lasted for six weeks at 20 m/min on a 0% gradient for 10-60 min/day. Rats in the L-arginine-treated groups drank water containing 2.5% L-arginine. According to histochemical identification of the capillary profile, in the soleus muscle the capillary-to-fiber (C:F) ratio showed a significantly greater value in the L-arginine-treated training group than in both the sedentary control and training groups. Training with L-arginine significantly increased the C:F ratio in the subendocardium of the left ventricle, whereas training alone did not. In the plantaris muscle, training with or without L-arginine significantly increased the capillary density, but it did not affect the C:F ratio. A Western blot analysis showed that training with L-arginine significantly increased VEGF protein expression by 2.9-fold in the soleus muscle and by 1.7-fold in the left ventricle, but the increase with training alone was insignificant. The tissue endothelial nitric oxide synthase protein levels were significantly increased in both the soleus (by 1.3-fold) and the left ventricle (by 1.4-fold) only after training with L-arginine supplementation. In the plantaris muscle, these protein levels did not change after either training or L-arginine treatment. The present results suggest that in middle-aged rats, L-arginine administration caused additional effects on exercise-induced angiogenesis by presumably promoting VEGF expression in the hind-leg muscle as well as in the left ventricle.
Suzuki
Junichi
J
Laboratory of Sports Physiology, Research and Education Center for Winter Sports, Hokkaido University of Education, Ainosato 5-3, Kita-ku, Sapporo, Hokkaido, 002-8502 Japan. suzuki@sap.hokkyodai.ac.jp
D000375:Aging / Q000502:physiology*; D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D015153:Blotting, Western; D002196:Capillaries / Q000166:cytology; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D006352:Heart Ventricles / Q000378:metabolism; D006614:Hindlimb / Q000098:blood supply; D006651:Histocytochemistry; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000502:physiology
D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D001120:Arginine; D052250:Nitric Oxide Synthase Type III