Exploring the protective mechanisms and therapeutic potential of carnosic acid against acute respiratory distress syndrome through molecular docking, molecular dynamics and experimental verification.

In the present study, a method combining network pharmacology prediction and experimental verification was used to clarify the protective mechanisms and therapeutic benefits of carnosic acid (CA) against acute respiratory distress syndrome (ARDS). Network pharmacology analysis was initially carried out to identify key targets and pathways for CA in ARDS. In vitro studies were performed using mouse alveolar macrophages (MH-S cells) to examine the impact of CA on pyroptosis and oxidative stress triggered by lipopolysaccharide (LPS)/ATP. Pyroptosis was evaluated through Annexin V/PI staining, measurement of IL-1β and IL-18 levels, and expression analysis of pyroptosis-related genes. Assessment of oxidative stress involved measuring malondialdehyde, myeloperoxidase and superoxide dismutase levels, as well as intracellular reactive oxygen species (ROS) levels. Western blotting and immunofluorescence analysis were employed to investigate nuclear factor erythroid 2-related factor 2 (Nrf2) expression and nuclear translocation. Additionally, an in vivo ARDS mouse model was developed to further validate the therapeutic efficacy of CA through assessment of lung injury, inflammation and oxidative stress markers. Network pharmacology profiling revealed Nrf2 as the pivotal molecular target of CA, with pathway enrichment analysis highlighting its involvement in ROS homeostasis and programmed cell death pathways. Molecular docking analysis demonstrated a stable binding affinity between CA and Nrf2. In vitro experimental analysis revealed that CA notably reduced LPS/ATP-induced pyroptosis and oxidative stress, therefore reducing apoptosis, downregulating pyroptosis-related gene expression, and enhancing Nrf2 expression and nuclear translocation in MH-S cells. In vivo validation in the murine ARDS model demonstrated that CA treatment effectively mitigated pulmonary pathological damage, suppressed pyroptotic signaling pathways and reduced oxidative stress biomarkers. The present integrative study demonstrated that CA may protect against ARDS by targeting Nrf2, suppressing oxidative stress and pyroptosis. These findings provide a mechanistic understanding of CA and warrant further translational research for clinical application in ARDS management.