Objective Lung contusion (LC) is an independent risk factor for Adult Respiratory Distress Syndrome (ARDS). 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 sub-units 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 afterwards; 100 μg of plasmid DNA coding for the α,β of the Na+/K+-ATPase pump were instilled into the lungs (LC EP-pump group). Contusion only (LC only) and a sham saline instillation group after contusion were used as controls (LC EP-sham). Using a BTX 830 Electroporator, 8 electrical pulses of 200-V/cm field strength were applied transthoracically. Mice were sacrificed at 24hr, 48hr and 72hr post-delivery. Bronchial alveolar lavage (BAL) was recollected to measure albumin and cytokines by ELISA. Pulmonary compliance was measured and lungs were subject to histopathologic analysis. Results Following 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 BAL levels of albumin, improved P-V 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 following LC.

Injured patients with lung contusion (LC) are at risk of developing bacterial pneumonia (PNA) followed by sepsis and death. A recent Genome-wide Association Study, showed FER gene expression positively correlating with survival rates among individuals with above conditions. We sought to determine if electroporation-mediated (EP) delivery of FER gene could indeed improve survival, in a lethal model of combined LC and PNA. C57BL/6 mice sustained unilateral LC, which preceded a 500 Klebsiella CFU inoculation by 6 hrs. In-between these insults, human FER plasmid (pFER) was introduced into the lungs followed by eight EP pulses applied externally (10ms at 200V/cm). Control groups included EP of empty vector (pcDNA3) or Na+/K+-ATPase genes (pPump) and no treatment (LC + PNA). We recorded survival, histology, lung mechanics, bronchial alveolar fluid (BAL), FER and inflammatory gene expression and bacteriology. The data shows that 7-day survival was significantly improved by pFER compared to control groups. pFER increased BAL monocytes and activated antibacterial response genes (NOS, Fizz). pFER treatment showed decreased lung and blood Klebsiella counts reaching, in some cases, complete sterilization. In conclusion, FER gene delivery promoted survival in LC+PNA mice via recruitment of activated immune cells, improving efficiency of bacterial clearance within contused lung