Satellite cell ablation attenuates short-term fast-to-slow fibre type transformations in rat fast-twitch skeletal muscle.
The purpose of this time-course study was to determine whether satellite cell ablation within rat tibialis anterior (TA) muscles exposed to short-term chronic low-frequency stimulation (CLFS) would limit fast-to-slow fibre type transformations. Satellite cells of the left TA were ablated by exposure to gamma-irradiation before 1, 2, 5 or 10 days of CLFS and 1 week later where required. Control groups received only CLFS or a sham operation. Continuous infusion of 5-bromo-2'-deoxyuridine revealed that CLFS first induced an increase in satellite cell proliferation at 1 day, up to a maximum at 10 days over control (mean +/- SEM, 5.7 +/- 0.7 and 20.4 +/- 1.0 versus 1.5 +/- 0.2 mm(-2), respectively, P < 0.007) that was abolished by gamma-irradiation. Myosin heavy chain mRNA, immunohistochemical and sodium dodecyl sulfate polyacrylamide gel electrophoresis analyses revealed CLFS-induced fast-to-slow fibre type transformation began at 5 days and continued at 10 days; in those muscles that were also exposed to gamma-irradiation, attenuation occurred within the fast fibre population, and the final fast-twitch to slow-twitch adaptation did not occur. These findings indicate satellite cells play active and obligatory roles early on in the time course during skeletal muscle fibre type adaptations to CLFS.
Martins
Karen J B
KJ
Exercise Biochemistry Laboratory, Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB, Canada T6G 2H9.
Murdoch
Gordon K
GK
Shu
Yang
Y
Harris
R Luke W
RL
Gallo
Maria
M
Dixon
Walter T
WT
Foxcroft
George R
GR
Gordon
Tessa
T
Putman
Charles T
CT
D000222:Adaptation, Physiological; D000818:Animals; D049109:Cell Proliferation / Q000528:radiation effects; D004558:Electric Stimulation; D005720:Gamma Rays; D006649:Histocompatibility Antigens / Q000378:metabolism; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology* / Q000648:ultrastructure; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology* / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology* / Q000528:radiation effects
D006649:Histocompatibility Antigens; D020033:Protein Isoforms