Disorganization of honey-comb immunoreactive pattern of desmin and plectin in rat atrophic soleus muscle fiber induced by hindlimb suspension.
Immunoreactivity for desmin, plectin and alpha-actinin was investigated in rat atrophic soleus muscle fibers induced by hindlimb suspension between 1 and 4 weeks (hindlimb suspension group, HSG), and compared with that of the control group (CG). Some of the HSG for 4 weeks were allowed unrestricted cage activity for 2 weeks as the recovery group (RG). In the cross-sectioned muscle fibers of the CG, desmin and plectin showed honey-comb immunoreactive patterns extending throughout the sarcoplasm. Superimposed images by double immunofluorescence labeling showed overlapping of both immunoreactivities. In the longitudinally sectioned profiles, superimposed images of alpha-actinin and desmin were overlapped at the level of Z-discs. The focal disorganization of the above honeycomb immunoreactive patterns, followed by the reduction of the cross-sectional area (CSA) of atrophic soleus muscle fibers and the appearance of Z-streaming, uniquely arose in the HSG from the first week and extended throughout the sarcoplasm in proportion to the suspension period. Such honey-comb patterns of both desmin and plectin were already restored in the RG at 2 weeks, followed by the disappearance of Z-streaming, prior to the recovery of the CSA. These findings indicate that the disorganization of topological and structural relationships of desmin and plectin with Z-discs surrounding individual myofibrils is primarily evoked, which leads to Z-streaming of atrophic soleus muscle fibers, and that the restoration of the muscle activity results in an early arrangement recovery of desmin and plectin around myofibrils.
Nara
S
S
Department of Rehabilitation Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan. so-nara@med.uoeh-u.ac.jp
Hachisuka
K
K
Furukawa
H
H
Doi
Y
Y
Kudo
H
H
Fujimoto
S
S
D000818:Animals; D003598:Cytoskeletal Proteins / Q000276:immunology / Q000378:metabolism; D003893:Desmin / Q000276:immunology / Q000378:metabolism*; D049030:Dystroglycans; D019417:Hindlimb Suspension; D007381:Intermediate Filament Proteins / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D051190:Plectin; D051381:Rats; D017208:Rats, Wistar
D003598:Cytoskeletal Proteins; D003893:Desmin; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; C495334:Plec protein, rat; D051190:Plectin; D049030:Dystroglycans