SOD1 and acute respiratory distress syndrome: In order to explore the therapeutic effects and the related mechanism of LMWH nebulization on ALI, we observed the arterial blood gas, total protein content in bronchoalveolar lavage fluid, lung wet/dry weight ratio, malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, and Akt phosphorylation after establishing the model of ALI rabbits.