Background  Seawater inhalation lung injury is a critical respiratory condition with high mortality rate and a lack of effective treatment methods. Perfluorocarbon (PFC) is a colorless, odorless and inert organic compound, and current studies have found that PFC exhibits anti-inflammatory, antioxidant, and lung injury reducing effects in a variety of animal models of acute lung injury. However, there is no research on the intervention effects of PFC nebulized inhalation on seawater inhalation lung injury.

  Objective  To investigate the therapeutic effect of PFC aerosol inhalation on lung injury induced by seawater inhalation.

  Methods  Thirty-two male SD rats were randomly divided into normal saline group (N group), perfluorocarbon aerosol inhalation group (P group), seawater inhalation + normal saline group (SW group), seawater inhalation + PFC aerosol inhalation group (SP group), with 8 rats in each group. In the SW group and SP group, normal saline (2 mL/kg) and PFC (2 mL/kg) were inhaled through air tube at 30 minutes after the establishment of seawater inhalation lung injury model. Lung tissue, peripheral blood, and alveolar lavage fluid were taken at 4 hours after modeling to detect histopathology and inflammatory index (TNF-α, IL-1β, IL-6), oxidative stress indicators (MPO, MDA, SOD), lung wet to dry ratio, alveolar lavage fluid protein concentration, and the right lower lung was taken for HE staining. Another 16 male SD rats were also divided into 4 groups (with 4 rats in each group as above). Each group was injected with 2% Evans blue dye (20 mg/kg) through the right femoral vein at 30 minutes before execution to determine the content of Evans blue in lung tissue.

  Results  Compared with N group, the lung injury in the SW group was more serious, the pathological score of lung injury was higher (P<0.05), and TNF-α, IL-1β, IL-6, MDA, MPO in serum and BALF, the wet dry ratio of lung tissue, the protein content of alveolar lavage fluid and Evans blue level of lung tissue increased significantly (P<0.05), while SOD content decreased (P<0.05). PFC aerosol inhalation after seawater inhalation could significantly reduce the pathological score of lung injury, TNF-α, IL-1β in serum and BALF, IL-6 in BALF, MDA in serum, protein content in BALF, wet to dry ratio and Evans blue content in lung tissue (P<0.05), while SOD content was significantly increased (P<0.05). The IL-6 and MPO in serum were not significantly different between SW group and SP group.

  Conclusion  Perfluorocarbon aerosol inhalation can significantly alleviate lung injury induced by seawater inhalation, and its mechanism may be related to the improvement of pulmonary inflammation, oxidative stress, and alveolar capillary permeability.