title: Oxygen modulates the glutathione peroxidase activity during the L6 myoblast early differentiation process.
abstract: OBJECTIVE
  This work aims to study the regulation of the glutathione peroxidase and catalase activities in myoblasts from the L6 line exposed to 21%, 5% and 1% O2 during the cell differentiation.
  
  
  METHODS
  Rat L6 myoblasts were grown in 1%, 5% or 21% O2 in the presence or absence of N-acetyl cysteine. The cell proliferation was evaluated by determining the doubling time and kinetics of cultures by counting cells. The cell differentiation was analyzed by determining the myogenic fusion index using antibodies against the myosin heavy chain. The glutathione peroxidase and catalase activities were assayed. The p110-PI3K/Thr308-Akt pathway was studied using western blotting. The oxidative status of the cells was carried out by determining TBARS.
  
  
  RESULTS
  5% O2 improves the glutathione peroxidase activity, p110-PI3K/Thr308-Akt pathway and differentiation while 1% O2 alters all these parameters compared to 21% O2. NAC (0.5 mM) can prevent the deleterious effects of hypoxia (1% O2) on the L6 myoblast proliferation and enhances the myoblast differentiation when exposed to 21% O2. TBARS are reduced in 5% O2 compared to both 21% and 1% O2.
  
  
  CONCLUSIONS
  The glutathione peroxidase activity and p110-PI3K/Thr308-Akt are both modulated in the same way by oxygen.
authors.affiliation: Paris Cité Sorbonne, Université Paris 13, EA 2363 Réponses Cellulaires et Fonctionnelles à l'Hypoxie, Paris, France.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Hidalgo
authors.forename: Dominique
authors.initials: D
authors.lastname: Marchant
authors.forename: Patricia
authors.initials: P
authors.lastname: Quidu
authors.forename: Karima
authors.initials: K
authors.lastname: Youcef-Ali
authors.forename: Jean P
authors.initials: JP
authors.lastname: Richalet
authors.forename: Michele
authors.initials: M
authors.lastname: Beaudry
authors.forename: Sophie
authors.initials: S
authors.lastname: Besse
authors.forename: Thierry
authors.initials: T
authors.lastname: Launay
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D019070:Cell Lineage / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media / Q000494:pharmacology; D005979:Glutathione Peroxidase / Q000378:metabolism*; D032446:Myoblasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010100:Oxygen / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D003470:Culture Media; D017382:Reactive Oxygen Species; D005979:Glutathione Peroxidase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D010100:Oxygen; D000111:Acetylcysteine