title: Intermittent whole-body vibration attenuates a reduction in the number of the capillaries in unloaded rat skeletal muscle.
abstract: BACKGROUND
  Whole-body vibration has been suggested for the prevention of muscle mass loss and muscle wasting as an attractive measure for disuse atrophy. This study examined the effects of daily intermittent whole-body vibration and weight bearing during hindlimb suspension on capillary number and muscle atrophy in rat skeletal muscles.
  
  
  METHODS
  Sixty male Wistar rats were randomly divided into four groups: control (CONT), hindlimb suspension (HS), HS + weight bearing (WB), and HS + whole-body vibration (VIB) (n = 15 each). Hindlimb suspension was applied for 2 weeks in HS, HS + WB, and HS + VIB groups. During suspension, rats in HS + VIB group were placed daily on a vibrating whole-body vibration platform for 20 min. In HS + WB group, suspension was interrupted for 20 min/day, allowing weight bearing. Untreated rats were used as controls.
  
  
  RESULTS
  Soleus muscle wet weights and muscle fiber cross-sectional areas (CSA) significantly decreased in HS, HS + WB, and HS + VIB groups compared with CONT group. Both muscle weights and CSA were significantly greater in HS + WB and HS + VIB groups compared with HS group. Capillary numbers (represented by capillary-to-muscle fiber ratio) were significantly smaller in all hindlimb suspension-treated groups compared with CONT group. However, a reduction in capillary number by unloading hindlimbs was partially prevented by whole-body vibration. These findings were supported by examining mRNA for angiogenic-related factors. Expression levels of a pro-angiogenic factor, vascular endothelial growth factor-A mRNA, were significantly lower in all hindlimb suspension-treated groups compared with CONT group. There were no differences among hindlimb suspension-treated groups. Expression levels of an anti-angiogenic factor, CD36 (receptor for thrombospondin-1) mRNA, were significantly higher in all hindlimb suspension-treated groups compared with CONT group. Among the hindlimb suspension-treated groups, expression of CD36 mRNA in HS + VIB group tended to be suppressed (less than half the HS group).
  
  
  CONCLUSIONS
  Our results suggest that weight bearing with or without vibration is effective for disuse-derived disturbance by preventing muscle atrophy, and whole-body vibration exercise has an additional benefit of maintaining microcirculation of skeletal muscle.
authors.forename: Akinori
authors.initials: A
authors.lastname: Kaneguchi
authors.affiliation: Department of Rehabilitation, Faculty of Rehabilitation, Hiroshima International University, 555-36, Gakuendai, Kurose, Higashi-Hiroshima, Hiroshima, Japan. j-ozawa@hs.hirokoku-u.ac.jp.
authors.forename: Junya
authors.initials: J
authors.lastname: Ozawa
authors.forename: Seiichi
authors.initials: S
authors.lastname: Kawamata
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kurose
authors.forename: Kaoru
authors.initials: K
authors.lastname: Yamaoka
mesh_terms: D000818:Animals; D002196:Capillaries / Q000473:pathology; D019417:Hindlimb Suspension / Q000009:adverse effects*; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000473:pathology; D009133:Muscular Atrophy / Q000473:pathology / Q000517:prevention & control*; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar; D014732:Vibration / Q000627:therapeutic use*; D016474:Weight-Bearing