title: [Effects of acute hypoxia and intermittent hypoxic acclimatization on vascular endothelial growth factor gene expression in HepG2 cells].
abstract: OBJECTIVE
  To explore the influence of acute hypoxia and intermittent hypoxic acclimatization on vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1alpha (HIF-1alpha) gene expression in HepG2 cells underlying their possible biological significance.
  
  
  METHODS
  HepG2 was cultured in 1% O2 for 24 hours, then in 21% O2 for another 24 hours, which composed a hypoxic exposure cycle. After 6 cycles, HepG2 cells reached the status of hypoxic acclimatization. Gene transcription and translation of VEGF and HIF-1alpha were detected with Northern blot and Western blot methods.
  
  
  RESULTS
  Acute hypoxia could induce gene transcription and translation of VEGF and HIF-1alpha. After intermittent hypoxia acclimatization, the contents of VEGF and HIF-1alpha mRNA were 108.6% +/- 17.7% and 116.7% +/- 19.8% of those in normoxic control cells, while the protein contents were significantly increased to 1.4 and 2.7 times of those in control cells, respectively (P < 0.05). The protein expression levels of VEGF and HIF-1alpha were decreased in cells subjected to hypoxia acclimatization compared to cells treated with acute hypoxia.
  
  
  CONCLUSIONS
  When HepG2 cells reached the status of hypoxic acclimatization, the acute hypoxia-induced increment of VEGF gene transcription and translation in cells were inhibited, in which HIF-1alpha might play an important role.
authors.affiliation: Key Research Laboratory of Wound Repair, 304th Hospital of PLA, Beijing 100037, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Jia-Pei
authors.initials: JP
authors.lastname: Chen
authors.forename: Shi-Li
authors.initials: SL
authors.lastname: Ge
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Fu
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Cong
mesh_terms: D000064:Acclimatization / Q000235:genetics*; D015687:Cell Hypoxia / Q000235:genetics; D015870:Gene Expression; D056945:Hep G2 Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics; D010100:Oxygen / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D010100:Oxygen