title: Early-onset calorie restriction conserves fiber number in aging rat skeletal muscle.
abstract: The purpose of this work was to determine the effect of early-onset calorie restriction on sarcopenia in the aging rat. Ad libitum (AL) fed animals were examined at 5, 18, 21, and 36 months of age. Calorie-restricted (CR) rats, 40% restricted since 4 months of age, were examined at 21 and 36 months of age. By 36 months, vastus lateralis, rectus femoris and soleus muscles, from AL-fed rats, had significant muscle mass and fiber loss, and reduced muscle cross-sectional area. Mean fiber diameter decreased with age in the vastus lateralis and rectus femoris but not the soleus of AL-fed rats. The number of Type I fibers significantly increased in the vastus lateralis with age. Calorie restriction did not prevent muscle mass loss with age; however, it significantly reduced muscle mass loss between 21 and 36 months of age compared with age-matched AL cohorts. Calorie restriction prevented fiber loss with age, and this conservation of fiber number reduced muscle mass loss with age.
authors.affiliation: Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors.forename: Susan H
authors.initials: SH
authors.lastname: McKiernan
authors.forename: Entela
authors.initials: E
authors.lastname: Bua
authors.forename: Jennifer
authors.initials: J
authors.lastname: McGorray
authors.forename: Judd
authors.initials: J
authors.lastname: Aiken
mesh_terms: D000375:Aging / Q000473:pathology*; D000818:Animals; D001835:Body Weight; D031204:Caloric Restriction; D003433:Crosses, Genetic; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000145:classification / Q000648:ultrastructure*; D018482:Muscle, Skeletal / Q000254:growth & development / Q000648:ultrastructure*; D009133:Muscular Atrophy / Q000473:pathology / Q000517:prevention & control*; D009929:Organ Size; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344