title: Increased myofiber remodelling and NFATc1-myonuclear translocation in rat postural skeletal muscle after experimental vestibular deafferentation.
abstract: BACKGROUND
  The vestibular system undergoes considerable modification during spaceflight [5]. This is paralleled by microgravity-induced muscle atrophy [6]. However, the possibility of vestibulo-autonomic regulatory mechanisms affecting skeletal muscle structure and function have not yet been addressed.
  
  
  OBJECTIVE
  We hypothesise that the vestibular system affects anti-gravitational skeletal muscle phenotype composition, size and the transcriptional factor called nuclear factor of activated T cells (NFATc1).
  
  
  METHODS
  In a laboratory study, we examined the morphological and histochemical properties including intramyocellular NFATc1 changes in slow-type soleus muscle of chemically labyrinthectomized rats (VLx; n=8) compared to a control group (Sham; n=6) after a period of one month.
  
  
  CONCLUSIONS
  Neurochemical vestibular deafferentation resulted in smaller myofibre sizes, altered myofibre phenotype composition, high yields of hybrid fibre formation, and reduced myonuclear NFATc1 accumulation as signs of slow-type myofibre atrophy, myofibre type remodelling, and altered nuclear transcriptional activity in the postural soleus muscle of rats. We propose that vestibulo-autonomic modification of skeletal muscles occurs during prolonged microgravity. Our findings are likely to have implications for vestibular rehabilitation in clinical settings.
authors.affiliation: Department of Vegetative Anatomy, Neuromuscular Group, Charité - University Medicine Berlin, Berlin, Germany Center for Space Medicine Berlin (ZWMB), Berlin, Germany.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Luxa
authors.forename: Michele
authors.initials: M
authors.lastname: Salanova
authors.forename: Gudrun
authors.initials: G
authors.lastname: Schiffl
authors.forename: Martina
authors.initials: M
authors.lastname: Gutsmann
authors.forename: Stéphane
authors.initials: S
authors.lastname: Besnard
authors.forename: Pierre
authors.initials: P
authors.lastname: Denise
authors.forename: Andrew
authors.initials: A
authors.lastname: Clarke
authors.forename: Dieter
authors.initials: D
authors.lastname: Blottner
mesh_terms: D019412:Anatomy, Cross-Sectional; D000818:Animals; D015415:Biomarkers; D048429:Cell Size; D003714:Denervation; D007758:Ear, Inner / Q000502:physiology; D005260:Female; D007150:Immunohistochemistry; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000473:pathology*; D010641:Phenotype; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014722:Vestibule, Labyrinth / Q000502:physiology*; D014893:Weightlessness; D018474:Weightlessness Simulation
chemical_list: D015415:Biomarkers; C584440:NFATC1 protein, rat; D014157:Transcription Factors
keywords: Labyrinthectomy (vestibular lesion); NFATc1 (NFAT2); skeletal muscle soleus