title: The Green Tea Polyphenol Epigallocatechin-3-Gallate (EGCg) Attenuates Skeletal Muscle Atrophy in a Rat Model of Sarcopenia.
abstract: OBJECTIVE
  Sarcopenia-the loss of muscle mass and functionality occurring with age-is a pervasive problem with few effective treatments beyond exercise. We examined the ability of the green tea catechin, epigallocatechin-3-gallate (EGCg), to impact muscle mass and the molecular pathway involved in muscle atrophy in a rat model of sarcopenia.
  
  
  METHODS
  20-month-old Sprague-Dawley rats were treated for 8 weeks with control diet or control plus 200mg/kg body weight of EGCg diet.
  
  
  RESULTS
  EGCg-supplemented animals had significantly greater gastrocnemius muscle mass than the aged controls, and showed a trend for increased muscle fiber cross-sectional areas (CSA) (p=0.06). These changes were associated with significantly lower protein expressions of the intramuscular 19S and 20S proteasome subunits and the MuRF1 and MAFbx ubiquitin ligases in the EGCg-treated animals. Proteasome activity as determined by 'Chymotrypsin-like' enzyme activity was also significantly reduced by EGCg. Muscle mRNA expression of IL-15 and IGF-1 were significantly increased in the EGCg group vs. the aged controls. In comparison to younger adult animals (6 month), the protein expression of 19S, 20S, MuRF1, MAFbx, and myostatin were increased between approximately 4- and 12-fold in the aged controls, but only up to ~2-fold in the aged EGCg animals.
  
  
  CONCLUSIONS
  EGCg supplementation was able to preserve muscle in sarcopenic rats, partly through attenuating protein degradation via the ubiquitin-proteasome pathway, together with increased expression of anabolic factors.
authors.affiliation: Suzette L. Pereira, Ph.D. Abbott Nutrition, Strategic R and D, RP4-3, 3300 Stelzer Road, Columbus, OH 43219, suzette.pereira@abbott.com, Tel: 1-614-624-4625, Fax: 1-614-727-4625.
authors.forename: B M
authors.initials: BM
authors.lastname: Meador
authors.forename: K A
authors.initials: KA
authors.lastname: Mirza
authors.forename: M
authors.initials: M
authors.lastname: Tian
authors.forename: M B
authors.initials: MB
authors.lastname: Skelding
authors.forename: L A
authors.initials: LA
authors.lastname: Reaves
authors.forename: N K
authors.initials: NK
authors.lastname: Edens
authors.forename: M J
authors.initials: MJ
authors.lastname: Tisdale
authors.forename: S L
authors.initials: SL
authors.lastname: Pereira