title: [The relationship between reactive oxygen species-dependent activation of p38 MAPK and the expression of tumor necrosis factor-α in cultured cardiomyocytes].
abstract: OBJECTIVE
  To investigate the role of p38 mitogen-activated protein kinase(MAPK) in lipopolysaccharide (LPS)-induced tumor necrosis factor-α (TNF-α) expression in neonatal rat cardiomyocytes and to determine the relationship between reactive oxygen species (ROS) and p38 MAPK activation.
  
  
  METHODS
  Cardiomyocytes were isolated from neonatal Sprague-Dawley rats and cultured by differential adhesion. Expression of TNF-α was determined in culture medium by ELISA. Activation of p38 MAPK was determined by Western blot analysis with phospho-specific antibody. ROS generation in cardiomyocytes was determined by peroxide specific probe 2', 7'-dichlorofluorescin diacetate (DCF-DA).
  
  
  RESULTS
  In cardiomyocytes stimulated with LPS, the content of TNF-α in culture medium correlated with the activity of p38 MAPK in a time-dependent manner. The activation of p38 was observed after stimulation of 1 mg/L LPS for 1 h. TNF-α accumulated significantly in culture medium at 3 h after stimulation of LPS (P<0.05), which was remarkably attenuated by pretreatment with p38 MAPK specific inhibitor SB203580 (P<0.01). Furthermore, the production of ROS in cardiomyocytes stimulated with LPS was also increased at 1 h after stimulation of LPS, consistent with p38 MAPK activity. Pretreatment with antioxidants such as N-acetylcysteine and diphenyleneiodonium significantly inhibited the activation of p38 MAPK compared with LPS control (P<0.05). There was no significance in the activity of p38 MAPK among antioxidants pretreatment and non-LPS control groups.
  
  
  CONCLUSIONS
  The activation of p38 MAPK plays an important role in TNF-α expression in LPS-stimulated cardiomyocytes and the increase of ROS production is prerequisite for the activation of p38 MAPK.
authors.affiliation: Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, China.
authors.forename: Fu-jun
authors.initials: FJ
authors.lastname: Shang
authors.forename: Jie-pin
authors.initials: JP
authors.lastname: Wang
authors.forename: Qiang-sun
authors.initials: QS
authors.lastname: Zheng
authors.forename: Xiong-tao
authors.initials: XT
authors.lastname: Liu
authors.forename: Yu-sheng
authors.initials: YS
authors.lastname: Xue
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Lian-you
authors.initials: LY
authors.lastname: Zhao
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D007093:Imidazoles; D008070:Lipopolysaccharides; D009861:Onium Compounds; D011725:Pyridines; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C007517:diphenyleneiodonium; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580; D000111:Acetylcysteine