[Effects of hypoxia on the proliferation of embryonic stem cells]

To investigate the effects of hypoxia on the proliferation of mouse embryonic stem cells (mouse ES cells) in vitro.

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.

(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.

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.