Remodeling of the cytoskeletal lattice in denervated skeletal muscle.
The effect of denervation-induced atrophy on the cytoskeletal lattice in rat fast- and slow-twitch skeletal muscle has been investigated. Immunochemical analyses and immunofluorescence microscopy experiments employing monospecific antibodies to dystrophin, desmin, and alpha-tubulin were carried out on intact and denervated muscles. The relative cellular content of dystrophin and desmin were reduced in the soleus muscle (slow-twitch), while significant increases were shown in the gastrocnemius muscle (fast-twitch). In both muscles, alpha-tubulin levels increased up to 12-fold as a function of time compared to control values. Immunofluorescence microscopy revealed a distinct rearrangement of the microtubule network toward a predominantly longitudinal alignment, which was accompanied by an increase in the density of the fluorescence. It is concluded that the relative increase of the three structural proteins in the fast-twitch gastrocnemius muscle may be related to the apparent resistance of this muscle type to denervation-induced atrophy. The increased alpha-tubulin content in denervated slow- and fast-twitch muscles could be indicative of an adaptive mechanism designed to maintain the integrity of the muscle fiber in view of eventual regenerative activities.
Boudriau
S
S
Laval University Hospital Research Center, Québec, Canada.
Côté
C H
CH
Vincent
M
M
Houle
P
P
Tremblay
R R
RR
Rogers
P A
PA
D000818:Animals; D003599:Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure; D003714:Denervation; D003893:Desmin / Q000378:metabolism; D016189:Dystrophin / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D007120:Immunochemistry; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000648:ultrastructure; D018656:Muscle Fibers, Fast-Twitch / Q000378:metabolism; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D014404:Tubulin / Q000378:metabolism
D003893:Desmin; D016189:Dystrophin; D014404:Tubulin