title: [Effects of hypoxia on the proliferation of embryonic stem cells].
abstract: OBJECTIVE
  To investigate the effects of hypoxia on the proliferation of mouse embryonic stem cells (mouse ES cells) in vitro.
  
  
  METHODS
  We observed the proliferation of ES cells by hematometery and BrdU-labeled flow cytometry (FCM), and we also detected the expression of hypoxia inducible factor-1a (HIF-1a) by RT-PCR.
  
  
  RESULTS
  (1) The number of ES cells after culturing in the hypoxia environment (3% O2 and 10% O2) for 24 hours were lesser than those in normoxia (20% O2). (2) The number of ES cells significantly increased after intermittent hypoxia (3% O2) stimulus for 10 minutes per day for 4 days. (3) We also observed the relation between the expression of HIF-1a and the proliferation of ES cells by RT-PCR. The results showed that the expression of HIF-1a had no significant change after ES cells were culturing in hypoxia environment (3% O2 and 10% O2) for 24 hours or in intermittent hypoxia (3% O2 and 10% O2) for 4 days.
  
  
  CONCLUSIONS
  These results suggest that intermittent hypoxia (3% O2) can significantly promote the proliferation of ES cells in vitro, while persistent hypoxia inhibits those, and the mechanism of these should be addressed in further.
authors.affiliation: Institute of Basic Medical Sciences, Academy of Military Medical Sciences,Beijing 100850, China.
authors.forename: Hui-qing
authors.initials: HQ
authors.lastname: Zhao
authors.forename: Ling-ling
authors.initials: LL
authors.lastname: Zhu
authors.forename: Tong
authors.initials: T
authors.lastname: Zhao
authors.forename: Li-ying
authors.initials: LY
authors.lastname: Wu
authors.forename: Ai-shi
authors.initials: AS
authors.lastname: Ding
authors.forename: Ming
authors.initials: M
authors.lastname: Fan
mesh_terms: D000818:Animals; D015687:Cell Hypoxia; D049109:Cell Proliferation; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology*; D051379:Mice