title: Exercise training prevents TNF-α induced loss of force in the diaphragm of mice.
abstract: BACKGROUND
  Inflammatory cytokines like tumor necrosis factor alpha (TNF-α) are elevated in congestive heart failure and are known to induce the production of reactive oxygen species as well as to deteriorate respiratory muscle function.
  
  
  OBJECTIVE
  Given the antioxidative effects of exercise training, the aim of the present study was to investigate if exercise training is capable of preventing a TNF-α induced loss of diaphragmatic force in mice and, if so, to elucidate the potential underlying mechanisms.
  
  
  METHODS
  Prior to intraperitoneal injection of TNF-α or saline, C57Bl6 mice were assigned to four weeks of exercise training or sedentary behavior. Diaphragmatic force and power generation were determined in vitro. Expression/activity of radical scavenger enzymes, enzymes producing reactive oxygen species and marker of oxidative stress were measured in the diaphragm.
  
  
  RESULTS
  In sedentary animals, TNF-α reduced specific force development by 42% concomitant with a 2.6-fold increase in the amount of carbonylated α-actin and creatine kinase. Furthermore, TNF-α led to an increased NAD(P)H oxidase activity in both sedentary and exercised mice whereas xanthine oxidase activity and intramitochondrial ROS production was only enhanced in sedentary animals by TNF-α. Exercise training prevented the TNF-α induced force reduction and led to an enhanced mRNA expression and activity of glutathione peroxidase. Carbonylation of proteins, in particular of α-actin and creatine kinase, was diminished by exercise training.
  
  
  CONCLUSIONS
  TNF-α reduces the force development in the diaphragm of mice. This effect is almost abolished by exercise training. This may be a result of reduced carbonylation of proteins due to the antioxidative properties of exercise training.
authors.affiliation: Heart Center Leipzig, University of Leipzig, Leipzig, Germany. norman.mangner@med.uni-leipzig.de
authors.forename: Norman
authors.initials: N
authors.lastname: Mangner
authors.forename: Axel
authors.initials: A
authors.lastname: Linke
authors.forename: Andreas
authors.initials: A
authors.lastname: Oberbach
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Kullnick
authors.forename: Stephan
authors.initials: S
authors.lastname: Gielen
authors.forename: Marcus
authors.initials: M
authors.lastname: Sandri
authors.forename: Robert
authors.initials: R
authors.lastname: Hoellriegel
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schuler
authors.forename: Volker
authors.initials: V
authors.lastname: Adams
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001706:Biopsy; D003964:Diaphragm / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D016166:Free Radical Scavengers / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000473:pathology; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D010805:Physical Conditioning, Animal; D011897:Random Allocation; D017382:Reactive Oxygen Species; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D010100:Oxygen