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[The influence of hypoxia inducible factor-1 alpha expression on apoptosis and proliferation of T lymphocyte in the Peyer's patches after burn with delayed fluid resuscitation in rats at high altitude].

OBJECTIVE
To explore the influence of hypoxia inducible factor-1 alpha (HIF-1 alpha) expression on the apoptosis and proliferation of T lymphocyte after severe burn with delayed fluid resuscitation at different altitude in rats.


METHODS
One hundred and thirty-two Wistar rats were subjected to burn injury [30% total body surface area (TBSA), III degree], at 1,517 metres and 3,848 metres above sea level, and they were randomly divided into three groups: delayed fluid resuscitation group (DFR, n=30 at each altitude), immediate fluid resuscitation group (IFR, n=30 at each altitude), and sham group (SG, n=6). The Peyer's patches were harvested from the ileum of rats at 6, 12, 24, 48 and 72 hours after burn respectively. The levels of HIF-1 alpha, CD3(+) and the rate of apoptosis in Peyer's patches were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), tissue microarray technology and immunohistochemistry.


RESULTS
The apoptosis rate in Peyer's patches was higher in DFR group than that in IFR group. The increase in HIF-1 alpha expression was observed mainly on cell nucleus in T lymphocytes. The expression levels of HIF-1 alpha in Peyer's patches were much higher in DFR group and IFR group than those in SG, and they were higher at 3 848 metres than those at 1 517 metres, and also higher in DFR group compared with IFR group (all P<0.05). The decrease in CD3(+) expression was observed mainly on cell membrane in T lymphocytes. The expression levels of CD3(+) in Peyer's patches were much higher in DFR group and IFR group than those in SG group, and the trough value appeared at 12 hours after burn (all P<0.05).


CONCLUSION
High expression of HIF-1 alpha may be responsible for the high apoptosis rate and decrease of T lymphocyte number in Peyer's patches after severe burn with delayed fluid resuscitation in rats at high altitude.