title: Satellite cell ablation attenuates short-term fast-to-slow fibre type transformations in rat fast-twitch skeletal muscle.
abstract: 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.
authors.affiliation: Exercise Biochemistry Laboratory, Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB, Canada T6G 2H9.
authors.forename: Karen J B
authors.initials: KJ
authors.lastname: Martins
authors.forename: Gordon K
authors.initials: GK
authors.lastname: Murdoch
authors.forename: Yang
authors.initials: Y
authors.lastname: Shu
authors.forename: R Luke W
authors.initials: RL
authors.lastname: Harris
authors.forename: Maria
authors.initials: M
authors.lastname: Gallo
authors.forename: Walter T
authors.initials: WT
authors.lastname: Dixon
authors.forename: George R
authors.initials: GR
authors.lastname: Foxcroft
authors.forename: Tessa
authors.initials: T
authors.lastname: Gordon
authors.forename: Charles T
authors.initials: CT
authors.lastname: Putman
mesh_terms: 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
chemical_list: D006649:Histocompatibility Antigens; D020033:Protein Isoforms