title: Dietary supplementation with shiikuwasha extract attenuates dexamethasone-induced skeletal muscle atrophy in aged rats.
abstract: BACKGROUND
  Skeletal muscle atrophy is caused by a variety of diseases and conditions. In particular, skeletal muscle atrophy in the elderly contributes to a loss of independence with advanced age and increases the risk of falling. However, the effect of food consumed on a daily basis on skeletal muscle atrophy has been the focus of little research. In this study, the effects of dietary supplementation with shiikuwasha extract or grape extract on dexamethasone-induced skeletal muscle atrophy were evaluated in aged rats.
  
  
  METHODS
  Aged male rats (15-month-old) were fed a diet supplemented with either 1 % shiikuwasha extract or 1 % grape extract for 19 days. During the last 5 days of the feeding period, rats were injected with dexamethasone to induce muscle atrophy.
  
  
  RESULTS
  Body weight and hind-limb muscle weight were significantly decreased by dexamethasone treatment. The supplementation of shiikuwasha extract showed no effect on body weight loss, but markedly attenuated tibialis anterior muscle weight loss induced by dexamethasone. On the other hand, grape extract did not affect muscle weight loss. Furthermore, shiikuwasha extract significantly reduced dexamethasone-induced expression of atrogin-1 and MuRF1 mRNA, but did not reduce LC3B-II protein levels.
  
  
  CONCLUSIONS
  These results suggest that shiikuwasha extract may partially inhibit the activation of the ubiquitin-proteasome system and may consequently attenuate skeletal muscle atrophy induced by dexamethasone in aged rats.
authors.affiliation: Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 1-83, 5-Chome, Higashihara, Zama, Kanagawa 252-8583 Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Sakata
authors.affiliation: Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 1-83, 5-Chome, Higashihara, Zama, Kanagawa 252-8583 Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Okamoto
authors.affiliation: Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 1-83, 5-Chome, Higashihara, Zama, Kanagawa 252-8583 Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Oshio
authors.affiliation: Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 1-83, 5-Chome, Higashihara, Zama, Kanagawa 252-8583 Japan.
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 1-83, 5-Chome, Higashihara, Zama, Kanagawa 252-8583 Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwamoto
authors.affiliation: Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 1-83, 5-Chome, Higashihara, Zama, Kanagawa 252-8583 Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Namba
authors.affiliation: Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co., Ltd., 1-83, 5-Chome, Higashihara, Zama, Kanagawa 252-8583 Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: Department of Agrobiology and Bioresources, Faculty of Agriculture, Utsunomiya University, 350, Mine-machi, Utsunomiya, Tochigi 321-8505 Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Yoshizawa
keywords: Glucocorticoid; Polymethoxylated flavones; Rat; Shiikuwasha; Skeletal muscle atrophy