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Updated: Aug 17, 2026

Pressure Controlled Ventilation to Induce Acute Lung Injury in Mice
Published on: May 5, 2011
Inducible nitric oxide synthase contributes to ventilator-induced lung injury
Xinqi Peng1, Raja-Elie E Abdulnour, Saad Sammani
1Division of Pulmonary and Critical Care Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
Rationale:
Inducible nitric oxide synthase (iNOS) has been implicated in the development of acute lung injury. Recent studies indicate a role for mechanical stress in iNOS and endothelial NOS (eNOS) regulation.
Objectives:
This study investigated changes in lung NOS expression and activity in a mouse model of ventilator-induced lung injury.
Methods:
C57BL/6J (wild-type [WT]) and iNOS-deficient (iNOS(-/-)) mice received spontaneous ventilation (control) or mechanical ventilation (MV; VT of 7 and 20 ml/kg) for 2 hours, after which NOS gene expression and activity were determined and pulmonary capillary leakage assessed by the Evans blue albumin assay.
Results:
iNOS mRNA and protein expression was absent in iNOS(-/-) mice, minimal in WT control mice, but significantly upregulated in response to 2 hours of MV. In contrast, eNOS protein was decreased in WT mice, and nonsignificantly increased in iNOS(-/-) mice, as compared with control animals. iNOS and eNOS activities followed similar patterns in WT and iNOS(-/-) mice. MV caused acute lung injury as suggested by cell infiltration and nitrotyrosine accumulation in the lung, and a significant increase in bronchoalveolar lavage cell count in WT mice, findings that were reduced in iNOS(-/-) mice. Finally, Evans blue albumin accumulation in lungs of WT mice was significant (50 vs. 15% increase in iNOS(-/-) mice compared with control animals) in response to MV and was prevented by treatment of the animals with the iNOS inhibitor aminoguanidine.
Conclusion:
Taken together, our results indicate that iNOS gene expression and activity are significantly upregulated and contribute to lung edema in ventilator-induced lung injury.
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