Adenovirus-mediated transfer of an Na+/K+-ATPase β1 subunit gene improves alveolar fluid clearance and survival in hyperoxic rats

Pulmonary edema is cleared via active Na+ transport by alveolar epithelial Na+/K+-ATPases and Na+ channels. Rats exposed to acute hyperoxia have a high mortality rate, decreased Na+/K+-ATPase function, and decreased alveolar fluid clearance (AFC), We hypothesized that Na+/K+-ATPase subunit gene overexpression could improve AFC in rats exposed to hyperoxia, We delivered 4 X 10(9) PFU of recombinant adenoviruses containing rat alpha (1) and beta (1) Na+/K+-ATPase subunit cDNAs (ad alpha (1) and ad beta (1), respectively) to rat lungs 7 days prior to exposure to 100% O-2 for 64 hr, As compared with controls and ad alpha (1), AFC in the ad beta (1) rats was increased by >300%. Permeability for large solutes was less in the ad beta (1) than in the other hyperoxia groups. Glutathione oxidation, but not superoxide dismutase activity, was increased only in the ad beta (1) group. Survival through 14 days of hyperoxia was 100% in the ad beta (1) group but was not different from hyperoxic controls in animals given ad alpha (1). Our data show that overexpression of a beta (1) Na+/K+-ATPase subunit augments AFC and improves survival in this model of acute lung injury via antioxidant-independent mechanisms. Conceivably, restoration of AFC via gene transfer of Na+/K+-ATPase subunit genes may prove useful for the treatment of acute lung injury and pulmonary edema.