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Increased expression of AQP 1 and AQP 5 in rat lungs ventilated with low tidal volume is time dependent.

Fabregat G, García-de-la-Asunción J, Sarriá B, Cortijo J, De Andrés J, Mata M, Pastor E, Belda FJ - PLoS ONE (2014)

Bottom Line: Lung oedema and alveolar-capillary membrane permeability did not change during MV.But in AQP-1 expression these differences were not found.AQPs may have a protective effect against the oedema induced by MV.

View Article: PubMed Central - PubMed

Affiliation: Hospital General Universitario, Valencia, Spain.

ABSTRACT

Background and goals: Mechanical ventilation (MV) can induce or worsen pulmonary oedema. Aquaporins (AQPs) facilitate the selective and rapid bi-directional movement of water. Their role in the development and resolution of pulmonary oedema is controversial. Our objectives are to determine if prolonged MV causes lung oedema and changes in the expression of AQP 1 and AQP 5 in rats.

Methods: 25 male Wistar rats were subjected to MV with a tidal volume of 10 ml/kg, during 2 hours (n = 12) and 4 hours (n = 13). Degree of oedema was compared with a group of non-ventilated rats (n = 5). The expression of AQP 1 and AQP 5 were determined by western immunoblotting, measuring the amount of mRNA (previously amplified by RT-PCR) and immunohistochemical staining of AQPs 1 and 5 in lung samples from all groups.

Results: Lung oedema and alveolar-capillary membrane permeability did not change during MV. AQP-5 steady state levels in the western blot were increased (p<0.01) at 2 h and 4 h of MV. But in AQP-1 expression these differences were not found. However, the amount of mRNA for AQP-1 was increased at 2 h and 4 h of MV; and for AQP 5 at 4 h of MV. These findings were corroborated by representative immunohistochemical lung samples.

Conclusion: In lungs from rats ventilated with a low tidal volume the expression of AQP 5 increases gradually with MV duration, but does not cause pulmonary oedema or changes in lung permeability. AQPs may have a protective effect against the oedema induced by MV.

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Inmunohistochemistry of AQP 5.The dye stakes the alveolar network and the surface of type 1 pneumocytes perfectly. Staining is more intense with longer MV exposure times (Groups 2H and 4H).
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pone-0114247-g010: Inmunohistochemistry of AQP 5.The dye stakes the alveolar network and the surface of type 1 pneumocytes perfectly. Staining is more intense with longer MV exposure times (Groups 2H and 4H).

Mentions: Immunohistochemical lung preparations of AQP-5 show the membranes of type 1 pneumocytes delimiting the alveolar network. The intensity of the staining increases with duration of MV (Fig. 10). AQP 1 samples show the network of the alveolar capillaries, as AQP-1 is found in endothelial cells and red blood cells but not in the pneumocytes covering the alveolus. In this case, image analysis does not show an increase in dye intensity in relation to MV time (Fig. 11).


Increased expression of AQP 1 and AQP 5 in rat lungs ventilated with low tidal volume is time dependent.

Fabregat G, García-de-la-Asunción J, Sarriá B, Cortijo J, De Andrés J, Mata M, Pastor E, Belda FJ - PLoS ONE (2014)

Inmunohistochemistry of AQP 5.The dye stakes the alveolar network and the surface of type 1 pneumocytes perfectly. Staining is more intense with longer MV exposure times (Groups 2H and 4H).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4260863&req=5

pone-0114247-g010: Inmunohistochemistry of AQP 5.The dye stakes the alveolar network and the surface of type 1 pneumocytes perfectly. Staining is more intense with longer MV exposure times (Groups 2H and 4H).
Mentions: Immunohistochemical lung preparations of AQP-5 show the membranes of type 1 pneumocytes delimiting the alveolar network. The intensity of the staining increases with duration of MV (Fig. 10). AQP 1 samples show the network of the alveolar capillaries, as AQP-1 is found in endothelial cells and red blood cells but not in the pneumocytes covering the alveolus. In this case, image analysis does not show an increase in dye intensity in relation to MV time (Fig. 11).

Bottom Line: Lung oedema and alveolar-capillary membrane permeability did not change during MV.But in AQP-1 expression these differences were not found.AQPs may have a protective effect against the oedema induced by MV.

View Article: PubMed Central - PubMed

Affiliation: Hospital General Universitario, Valencia, Spain.

ABSTRACT

Background and goals: Mechanical ventilation (MV) can induce or worsen pulmonary oedema. Aquaporins (AQPs) facilitate the selective and rapid bi-directional movement of water. Their role in the development and resolution of pulmonary oedema is controversial. Our objectives are to determine if prolonged MV causes lung oedema and changes in the expression of AQP 1 and AQP 5 in rats.

Methods: 25 male Wistar rats were subjected to MV with a tidal volume of 10 ml/kg, during 2 hours (n = 12) and 4 hours (n = 13). Degree of oedema was compared with a group of non-ventilated rats (n = 5). The expression of AQP 1 and AQP 5 were determined by western immunoblotting, measuring the amount of mRNA (previously amplified by RT-PCR) and immunohistochemical staining of AQPs 1 and 5 in lung samples from all groups.

Results: Lung oedema and alveolar-capillary membrane permeability did not change during MV. AQP-5 steady state levels in the western blot were increased (p<0.01) at 2 h and 4 h of MV. But in AQP-1 expression these differences were not found. However, the amount of mRNA for AQP-1 was increased at 2 h and 4 h of MV; and for AQP 5 at 4 h of MV. These findings were corroborated by representative immunohistochemical lung samples.

Conclusion: In lungs from rats ventilated with a low tidal volume the expression of AQP 5 increases gradually with MV duration, but does not cause pulmonary oedema or changes in lung permeability. AQPs may have a protective effect against the oedema induced by MV.

Show MeSH
Related in: MedlinePlus