Aerosolized Human Extracellular Superoxide Dismutase Prevents Hyperoxia‐Induced Lung Injury in Mouse Model

Objective An important issue in critical care medicine is the identification of ways to protect the lungs from oxygen toxicity and reduce systemic oxidative stress. The current study investigated the ability of aerosolized extracellular superoxide dismutase (EC‐SOD) to protect the lungs from hyperoxic injury. Methods Female CD‐1 mice were exposed in hyperoxia (FiO2 > 95%) to induce lung injury. The therapeutic effects of EC‐SOD via an aerosol delivery system for lung injury and systemic oxidative stress at 24, 48, 72 and 96 h of hyperoxia were measured by bronchoalveolar lavage, wet/dry ratio, histology, and 8‐oxo‐dG in lung tissue. Results After exposure to hyperoxia, the wet/dry weight ratio remained stable before day 2 but increased significantly after day 3. Treatment with aerosolized rhEC‐SOD increased the survival rate at day 3 under hyperoxia to 95.8%, which was significantly higher than that of the control group (57.1%) and albumin treated group (33.3%). The protective effects of EC‐SOD against hyperoxia were further confirmed by reduced lung edema and systemic oxidative stress. Conclusion The results encourage the use of an aerosol therapy with EC‐SOD in intensive care units to reduce oxidative injury in patients with severe hypoxemic respiratory failure, including acute respiratory distress syndrome (ARDS).