Effects of long-term denervation on skeletal muscle in old rats.
We compared the reactions to denervation of limb muscles between young adult and old rats. After denervation for up to 4 months in 24-month-old rats, limb muscles were removed and analyzed for contractile properties, morphology, and levels of several key molecules, including the peptide elongation factors eEF1A-1 and eEF1A-2/S1, myogenin, gamma-subunit of the acetylcholine receptor, and cyclin D3. The principal difference between denervated old and young muscle is a somewhat slower rate of atrophy in denervated older muscle, especially among the type II fibers. Expression levels of certain molecules were higher in old than in young control muscle, but after denervation, levels of these molecules increased to the same absolute values in both young and old rats. Although many aspects of postdenervation reactions do not differ greatly between young and old animals, the lesser degree of atrophy in the old rats may reflect significant age-based mechanisms.
Carlson
Bruce M
BM
Institute of Gerontology, University of Michigan, Ann Arbor, MI 48109-2007, USA. bcarl@umich.edu
Borisov
Andrei B
AB
Dedkov
Eduard I
EI
Khalyfa
Abdelnaby
A
Kostrominova
Tatiana Y
TY
Macpherson
Peter C D
PC
Wang
Eugenia
E
Faulkner
John A
JA
D000367:Age Factors; D000818:Animals; D015415:Biomarkers / Q000097:blood; D056743:Cyclin D3; D016213:Cyclins / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D009119:Muscle Contraction / Q000502:physiology; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology; D018008:Myogenin / Q000378:metabolism; D020648:Peptide Elongation Factor 1 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013995:Time; D016896:Treatment Outcome
D015415:Biomarkers; C534698:Ccnd3 protein, rat; D056743:Cyclin D3; D016213:Cyclins; C503236:Eef1a2 protein, rat; C503803:Myog protein, rat; D018008:Myogenin; D020648:Peptide Elongation Factor 1; D012333:RNA, Messenger