title: Sarcolemmal disruption in reloaded atrophic skeletal muscle.
abstract: The purpose of this study was to determine whether reloading of atrophied skeletal muscle after 28 days of hind-limb unloading (HU) would produce significant sarcolemmal membrane disruption before frank necrosis. Soleus and plantaris muscles were atrophied by HU. Adult female Wistar rats (N = 13) were killed at 28 days of unloading and 4 and 7 days of reloading after HU. Rat serum albumin was used as a marker for muscle fiber disruption. Dark intracellular staining with horseradish peroxidase-conjugated anti-rat serum albumin antibody was interpreted as evidence of membrane rupture. There was a significantly different time course of disruption between plantaris and soleus muscles, with a negative correlation between cell size and occurrence of disruption. Fourteen percent of plantaris fibers were wounded after HU, peaking at day 4 of reloading (20% of cross-sectional area). Soleus demonstrated disruption only on reloading peaking in severity at day 7 (14% of fibers). It was demonstrated that sarcolemmal disruption due to atrophy and reloading does not always progress to necrosis and degeneration by the 7th day of recovery.
authors.affiliation: School of Nursing, University of California, Los Angeles 90095-6918, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Kasper
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology; D005260:Female; D006614:Hindlimb / Q000473:pathology / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology; D009133:Muscular Atrophy / Q000473:pathology* / Q000503:physiopathology; D009929:Organ Size / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012508:Sarcolemma / Q000502:physiology / Q000648:ultrastructure*; D012709:Serum Albumin / Q000378:metabolism; D018474:Weightlessness Simulation
chemical_list: D012709:Serum Albumin