[Experimental study for lung fluid transport by epithelial cells and aquaporins].
OBJECTIVE
To explore the effects of aquaporins (AQP) 1, 4 on water transport between airspace and pulmonary capillary and high pressure pulmonary edema. The other purpose was to study the active alveolar fluid transport as well as alveolar fluid clearance (AFC) in different pH of airspace.


METHODS
The effects of AQP1, 4 on water transport between airspace and pulmonary capillary and high pressure pulmonary edema were studied by surface fluorescence methods and gravimetric method respectively, AFC and AFC in airspace with different pH were measured by isotope method.


RESULTS
AQP1 knockout inhibited water transport through pulmonary capillary and also reduced high pressure pulmonary edema. Salbutamol increased AFC, but it was reduced when propranolol was used together. AFC was improved by terbutaline, isoproterenol, salmeterol when pH > 2.5 in airspace, but the effect was reduced after pH < 2.5 in airspace. Sodium channel inhibitor, Benzamil, could also inhibit AFC.


CONCLUSIONS
AQP1 knockout significantly reduced water transport through alveolar capillary, and also reduced high pulmonary edema slightly. beta adrenergic stimulant improved AFC in mechanically ventilated rats. Intact airspace is very important for the function of AFC, however, the effect of AFC was impaired after lung injury induced by pH < 2.5 in airspace.
Bai
C
C
Department of Pulmonary Medicine, Zhongshan Hospital, Medical Center of Fudan University, Shanghai 200032, China.
Chen
Z
Z
Song
Y
Y
D000818:Animals; D020346:Aquaporins / Q000235:genetics / Q000502:physiology*; D001692:Biological Transport; D001693:Biological Transport, Active; D001826:Body Fluids / Q000378:metabolism*; D002199:Capillary Permeability / Q000502:physiology; D004847:Epithelial Cells / Q000378:metabolism*; D008168:Lung / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D011650:Pulmonary Alveoli / Q000378:metabolism; D011654:Pulmonary Edema / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D020346:Aquaporins