Medical ozone alleviates acute lung injury by enhancing phagocytosis targeting NETs via AMPK/SR-A1 axis

Acute lung injury (ALI) linked to sepsis has a high mortality rate, with limited treatment options available. In recent studies, medical ozone has shown the potential to alleviate inflammation and infection. Here, we aimed to evaluate therapeutic potential of medical ozone in a mouse model of the sepsis-induced ALI by measuring behavioral assessments, lung function, and blood flow. Protein levels were quantified by Western blotting. In vitro, we performed experiments on bone marrow-derived macrophages (BMDMs) to investigate the effect of adenosine monophosphate (AMP)-activated protein kinase (AMPK) inhibitors and agonists on their phagocytic activity. The results showed that medical ozone significantly improved the survival rate, ameliorated lung injury, and enhanced lung function and limb microcirculation in mice with ALI. Notably, medical ozone inhibited the formation of neutrophil extracellular traps (NETs), a crucial factor in the ALI development. Additionally, medical ozone counteracted the elevated levels of tissue factor, matrix metalloproteinase-9, and interleukin-1β. In the ALI mice, the effects of ozone were abolished, and BMDMs showed an impaired capacity to engulf NETs following the Sr-a1 knockout. Under normal physiological conditions, the administration of an AMPK antagonist showed similar effects on the Sr-a1 knockout, significantly inhibiting the phagocytosis of NETs by BMDMs. In contrast, AMPK agonists enhanced this phagocytic process. In conclusion, medical ozone may alleviate the sepsis-induced lung injury through the AMPK/SR-A1 pathway, thereby enhancing the phagocytosis of NETs by macrophages.