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Skeletal muscle adaptations to microgravity exposure in the mouse
Skeletal muscle adaptations to microgravity exposure in the mouse.
24
To investigate the effects of microgravity on murine skeletal muscle fiber size, muscle contractile protein, and enzymatic activity, female C57BL/6J mice, aged 64 days, were divided into animal enclosure module (AEM) ground control and spaceflight (SF) treatment groups. SF animals were flown on the space shuttle Endeavour (STS-108/UF-1) and subjected to approximately 11 days and 19 h of microgravity. Immunohistochemical analysis of muscle fiber cross-sectional area revealed that, in each of the muscles analyzed, mean muscle fiber cross-sectional area was significantly reduced (P < 0.0001) for all fiber types for SF vs. AEM control. In the soleus, immunohistochemical analysis of myosin heavy chain (MHC) isoform expression revealed a significant increase in the percentage of muscle fibers expressing MHC IIx and MHC IIb (P < 0.05). For the gastrocnemius and plantaris, no significant changes in MHC isoform expression were observed. For the muscles analyzed, no alterations in MHC I or MHC IIa protein expression were observed. Enzymatic analysis of the gastrocnemius revealed a significant decrease in citrate synthase activity in SF vs. AEM control.
Harrison BC, Allen DL, Girten B, Stodieck LS, Kostenuik PJ, Bateman TA, Morony S, Lacey D, Leinwand LA
Journal of applied physiology (Bethesda, Md. : 1985)
2003-12-01 00:00
95
6
2462-70
Adaptation, Physiological,Animals,Body Weight,Citrate (si)-Synthase,Female,Heart,Immunohistochemistry,Isomerism,Mice,Mice, Inbred C57BL,Muscle Fibers,Muscle, Skeletal,Myosin Heavy Chains,Organ Size,Oxidation-Reduction,Space Flight,Weightlessness,Myosin Heavy Chains,Citrate (si)-Synthase
Department of Kinesiology, University of Colorado, Boulder, CO 80309, USA
J. Appl. Physiol.
8750-7587
10.1152/japplphysiol.00603.2003
00603.2003
784
True
12882990
