title: Longitudinal characterization of functional, morphologic, and biochemical adaptations in mouse skeletal muscle with hindlimb suspension.
abstract: BACKGROUND
  Hindlimb unloading-induced muscle atrophy is often assessed after a homeostatic state is established, thus overlooking the early adaptations that are critical to developing this pattern of atrophy.
  
  
  METHODS
  Muscle function and physiology were characterized at 0, 1, 3, 7, and 14 days of hindlimb suspension (HS).
  
  
  RESULTS
  Reductions in muscle mass were maximal by Day 14 of HS. Functional strength and isolated muscle strength were reduced. MyHC-I and -IIa expressing fibers were reduced in size by Day 7 in the soleus and by Day 14 in the gastrocnemius (MyHC-I fibers only). Atrogin-1 and MuRF1 expression was increased by Day 1 in both the calf and tibialis anterior while IGF-1 expression was significantly reduced on Day 3. Phosphorylation of Akt was reduced on Day 14.
  
  
  CONCLUSIONS
  Insight into these early changes in response to HS improves understanding of the molecular and functional changes that lead to muscle atrophy.
authors.affiliation: Aerospace Engineering Sciences, BioServe Space Technologies, University of Colorado, Boulder, Colorado, USA.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Hanson
authors.forename: Brooke C
authors.initials: BC
authors.lastname: Harrison
authors.forename: Mary H
authors.initials: MH
authors.lastname: Young
authors.forename: Louis S
authors.initials: LS
authors.lastname: Stodieck
authors.forename: Virginia L
authors.initials: VL
authors.lastname: Ferguson
mesh_terms: D000200:Action Potentials; D000220:Adaptation, Biological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D015992:Body Mass Index; D004558:Electric Stimulation; D005080:Exercise Test; D005786:Gene Expression Regulation / Q000502:physiology*; D019417:Hindlimb Suspension; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008137:Longitudinal Studies; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018763:Muscle Fatigue / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000737:chemistry / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D013997:Time Factors; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D009124:Muscle Proteins; D000070584:Tripartite Motif Proteins; D007334:Insulin-Like Growth Factor I; C486691:Fbxo32 protein, mouse; D044843:SKP Cullin F-Box Protein Ligases; C499084:Trim63 protein, mouse; D044767:Ubiquitin-Protein Ligases; D018995:Myosin Heavy Chains
keywords: hindlimb suspension; myosin heavy chain; protein degradation; skeletal muscle; strength