Background:

Lung contusion (LC) is an independent risk factor for acute respiratory distress syndrome. The final common pathway in ARDS involves accumulation of fluid in the alveoli. In this study, we demonstrate the application of a potential gene therapy approach by delivering the Na+/K+-ATPase pump subunits in a murine model of LC. We hypothesized that restoring the activity of the pump will result in removal of excess alveolar fluid and additionally reduce inflammation.

Methods:

Under anesthesia, C57/BL6 mice were struck along the right posterior axillary line 1 cm above the costal margin with a cortical contusion impactor. Immediately afterward, 100 μg of plasmid DNA coding for the α, β of the Na+/K+-ATPase pump were instilled into the lungs (LC-electroporation-pump group). Contusion only (LC-only) and a sham saline instillation group after contusion were used as controls (LC-electroporation-sham). By using a BTX 830 electroporator, eight electrical pulses of 200 V/cm field strength were applied transthoracically. Mice were killed at 24 hours, 48 hours, and 72 hours after delivery. Bronchial alveolar lavage was recollected to measure albumin and cytokines by enzyme-linked immunosorbent assay. Pulmonary compliance was measured, and lungs were subject to histopathologic analysis.

Results:

After the electroporation and delivery of genes coding for the α, β subunits of the Na+/K+-ATPase pump, there was a significant mitigation of acute lung injury as evidenced by reduction in bronchial alveolar lavage levels of albumin, improved pressure volume curves, and reduced inflammation seen on histology.

Conclusion:

Electroporation-mediated gene transfer of the subunits of the Na+/K+-ATPase pump enhanced recovery from acute inflammatory lung injury after LC.