Satellite cell numbers in young and older men 24 hours after eccentric exercise.
We tested the hypothesis that the expansion of satellite cell numbers, 24 h after maximal eccentric knee extensor exercise, is blunted in older men. Muscle biopsies were obtained from the vastus lateralis of 10 young (23-35 years) and 9 older (60-75 years) men. Satellite cells were identified immunohistochemically using an antibody to neural cell adhesion molecule. After 92 maximal eccentric contractions, the mean number of satellite cells per muscle fiber increased to a greater extent among the young men (141%; P < 0.001) than older men (51%; P = 0.002) from preexercise levels. Similar results were obtained when satellite cells were expressed as a proportion of all sublaminar nuclei. We conclude that a single bout of maximal eccentric exercise increases satellite cell numbers in both age groups, with a significantly greater response among the young men. These data suggest that age-related changes in satellite cell recruitment may contribute to muscle regeneration deficits among the elderly.
Dreyer
Hans C
HC
Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, USA. hcdreyer@utmb.edu
Blanco
Cesar E
CE
Sattler
Fred R
FR
Schroeder
E Todd
ET
Wiswell
Robert A
RA
D000328:Adult; D000368:Aged; D000375:Aging; D001706:Biopsy; D002452:Cell Count; D049109:Cell Proliferation; D015444:Exercise; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009119:Muscle Contraction; D018485:Muscle Fibers, Skeletal / Q000166:cytology; D018482:Muscle, Skeletal / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D019006:Neural Cell Adhesion Molecules / Q000032:analysis; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology* / Q000502:physiology; D013739:Testosterone / Q000097:blood; D013997:Time Factors
D019006:Neural Cell Adhesion Molecules; D013739:Testosterone