title: L-arginine supplementation attenuates capillary regression without increasing integrated succinate dehydrogenase activity and VEGF expression in skeletal muscle during hindlimb unloading.
abstract: Decreased capillary number is observed in atrophied muscle. The change in capillary number is regulated by angiogenic factors. L-arginine enhances expression of endothelial nitric oxide synthase (eNOS), angiogenic factor, in skeletal muscle. Therefore, the aim of this study was to evaluate the effects of L-arginine supplementation on capillary regression during hindlimb unloading. Twenty-four male Wistar rats were divided into four treatment groups: (1) control, (2) L-arginine supplementation, (3) hindlimb unloading, and (4) hindlimb unloading with L-arginine supplementation. Hindlimb unloading resulted in a decrease of capillary-to-muscle fibre (C/F) ratio, eNOS expression, and integrated succinate dehydrogenase (SDH) activity. L-arginine supplementation attenuated the decrease in both eNOS expression and C/F ratio, although it did not increase integrated SDH activity in skeletal muscle. These results indicate that L-arginine supplementation is effective for maintaining capillary number in atrophied muscle, and that elevation of eNOS expression may be one mechanism associated with these responses.
authors.affiliation: Department of Rehabilitation Science, Kobe University, Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe 654-0142, Japan. fujino@phoenix.kobe-u.ac.jp.
authors.forename: Kensaku
authors.initials: K
authors.lastname: Uchida
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanaka
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Kondo
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ishihara
authors.forename: Hidemi
authors.initials: H
authors.lastname: Fujino
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001120:Arginine / Q000008:administration & dosage*; D002196:Capillaries / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D019587:Dietary Supplements; D004789:Enzyme Activation / Q000187:drug effects; D019417:Hindlimb Suspension; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism*; D009133:Muscular Atrophy / Q000188:drug therapy / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013385:Succinate Dehydrogenase / Q000378:metabolism*; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D001120:Arginine; D013385:Succinate Dehydrogenase