[Expression and modulation of aquaporin 5 in hyperoxia induced lung injury].
OBJECTIVE
To explore the expression and the modulation of aquaporin 5(AQP5) in hyperoxia induced lung injury.


METHODS
Sixty four Wistar rats of 2 weeks old, were randomly assigned to following groups (n=8): air group, hyperoxia 3, 7, 14 days groups, air + dexamethasone (Dex), hyperoxia 3, 7, 14 days + Dex groups. The rats were kept in oxygen chamber at normal pressure (O(2)> or =95%) in hyperoxia groups, and in normal pressure air (O(2)=21%) in room-air group, and the rats in Dex groups were injected with Dex (5 mg.kg(-1).d(-1)) intraperitoneally for 3 consecutive days in room-air or hyperoxia exposure. The expression of AQP5 mRNA level and the location were detected by reverse transcription-polymerase chain reaction and immunohistochemistry respectively.


RESULTS
AQP5 was strongly labeled in alveolar epithelial type I cells, and was also expressed in the secretory epithelium plasma membrane in the airway. The location of AQP5 in hyperoxia groups was not changed, but the expression of AQP5 mRNA had a notable gradual decline when the time of hyperoxia exposure was prolonged, compared to control group (all P<0.05). There was no difference in AQP5 mRNA level between hyperoxia groups and hyperoxia + Dex groups at different time points (all P<0.05).


CONCLUSIONS
The significant decrease in AQP5 may be an important factor of pulmonary edema formation in hyperoxia-induced lung injury. Dex does not have effect on modulating the AQP5 expression in acute lung injury.
Tan
Li-ping
LP
Intensive Care Unit, Children's Hospital, Chongqing University of Medical Science, Chongqing 400014, China.
Xu
Feng
F
Kuang
Feng-wu
FW
D000818:Animals; D051402:Aquaporin 5 / Q000235:genetics / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D018496:Hyperoxia / Q000150:complications* / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D055370:Lung Injury / Q000209:etiology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
C496040:Aqp5 protein, rat; D051402:Aquaporin 5; D012333:RNA, Messenger; D003907:Dexamethasone