Sarcolemmal disruption in reloaded atrophic skeletal muscle.
Kasper, Christine E.
School of Nursing and Jerry Lewis Neuromuscular Research Center,
University of California, Los Angeles, Los Angeles, California 90095
-6918
APStracts 2:0131A, 1995.
Sarcolemmal Disruption in Reloaded Atrophic Skeletal Muscle. The
purpose of this study was to determine if reloading of atrophied
skeletal muscle following 28 days of hindlimb unloading (HU) would
produce significant sarcolemmal membrane disruption prior to frank
necrosis. Soleus and plantaris muscles were were atrophied by HU.
Adult female Wistar rats (N = 13) were euthanized at 28 days of
unloading and 4 and 7 days of reloading following HU. Rat serum
albumin (RSA) was used as a marker for muscle fiber disruption. Dark
intracellular staining with horseradish peroxidase (HRP)-conjugated
anti-RSA 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 following HU, peaking at day 4 of reloading (20%
of cross-sectional area). Soleus demonstrated disruption only upon
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.
Received 25 August 1994; accepted in final form 16 March 1995.
APS Manuscript Number A898-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 4 April 1995.