Decreased expression of AQP1 and AQP5 in acute injured lungs in rats.
OBJECTIVE
To determine if aquaporin1 (AQP1) and aquaporin5 (AQP5) are expressed in the alveolar capillary membrane in rats. Moreover, to investigate the alteration of AQP1 and AQP5 in acute injured lungs.


METHODS
The distribution of AQP1 and AQP5 in alveolar capillary membrane were investigated by immunohistochemistry and immunoelectron microscopy with affinity-purified antibodies to human AQP1 and AQP5. To study the possibility that alveolar capillary membrane AQP1 and AQP5 undergo altered regulation, we established a rat model using alveolar instillation of lipopolysaccharide (LPS).


RESULTS
Immunolabelling showed AQP1 was stained primarily in the microvascular endotheli a of normal lungs, while AQP5 was expressed in type I pneumocytes. Immunohisto chemical analysis showed a significant decrease in the expression of AQP1 and AQP5 in injured lungs at 4h-48h after LPS instillation. AQP1 protein was resumed partly at 24h after LPS instillation and steroid administration, whereas AQP5 was unchanged.


CONCLUSIONS
The decreased expressions of AQP1 and AQP5 in injured lungs suggest that both of them may play a role in abnormal fluid transportation.
Jiao
Guangyu
G
Institute of Respiratory Disease, The First Clinical Hospital, China Medical University, Shenyang 110001, China. guangyujiao@263.net
Li
Erran
E
Yu
Runjiang
R
D000818:Animals; D051398:Aquaporin 1; D051402:Aquaporin 5; D020346:Aquaporins / Q000032:analysis*; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000633:toxicity; D008168:Lung / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins; D016253:Microscopy, Immunoelectron; D051381:Rats; D017207:Rats, Sprague-Dawley; D012128:Respiratory Distress Syndrome / Q000378:metabolism* / Q000473:pathology
C496022:Aqp1 protein, rat; C496040:Aqp5 protein, rat; D051402:Aquaporin 5; D020346:Aquaporins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D051398:Aquaporin 1