Microvascular angioadaptation after endurance training with L-arginine supplementation in rat heart and hindleg muscles.
This study was designed to examine whether dietary L-arginine supplementation modulates exercise-induced angiogenesis and vascular endothelial growth factor (VEGF) expression in female Wistar rats. Exercise training (running) lasted for 6 weeks at 25 m min-1 on a 20% gradient for 10-60 min day-1. Rats in the L-arginine-treated groups drank water containing 4% L-arginine. Histochemical identification of capillary profiles showed that training with L-arginine significantly increased the capillary/fibre (C/F) ratio in the subendocardium of the left ventricle, whereas training alone did not. Because of a significantly higher fibre cross-sectional area, a concomitant, but not significant, decrease in capillary density was also observed. In the hindleg muscles, training with L-arginine significantly increased the C:F ratio, although the degree of change was the same as that observed after training alone. Western blot analysis showed that training with L-arginine significantly increased VEGF protein expression by 1.7-fold in the left ventricle, while the increase with training alone was insignificant. In the soleus muscle, although VEGF protein expression was elevated insignificantly after training (2.8-fold), training with L-arginine significantly increased the protein levels (3.8-fold). Tissue endothelial nitric oxide synthase protein levels did not changed after either training or L-arginine treatment. The present results suggest that L-arginine supplementation causes additional effects on exercise-induced angiogenesis in the rat heart by promoting VEGF expression.
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
Junichi
J
Suzuki
D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D002196:Capillaries / Q000187:drug effects / Q000502:physiology*; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D006321:Heart / Q000187:drug effects; D006614:Hindlimb; D008833:Microcirculation; D018482:Muscle, Skeletal / Q000098:blood supply*; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*
D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D001120:Arginine