Chaiyin Granules Improve Acute Lung Injury by Regulating Gut Microbiota and Unsaturated Fatty Acid Mediated Wnt/β‐Catenin Signaling Pathway

AIM OF STUDY: This study aimed to investigate the efficacy and mechanism of Chaiyin granules (CY) in improving acute lung injury (ALI) based on the gut-lung axis. MATERIALS AND METHODS: UHPLC-ESI-Q-Exactive Orbitrap MS was used to analyze the active ingredients of CY. Establishment of lipopolysaccharide (LPS)-induced ALI mouse model and grouping: control, model, CYL (1.56 g/kg), CYM (3.12 g/kg), CYH (6.24 g/kg), and Dex (2 mg/kg) groups. The lung index and wet/dry (W/D) weight ratio of the lungs were calculated. The pathological damage of lung tissue was detected and evaluated using hematoxylin-eosin (H&E) staining. The expression of various inflammatory factors and oxidative stress-related factors was detected using cytometric bead array (CBA) and enzyme-linked immunosorbent assay (ELISA), respectively. The indicators characterizing intestinal barrier damage were detected through the application of Alcian blue periodic acid Schiff (AB-PAS) staining, ELISA, and western blot. Furthermore, gut microbiota were analyzed by 16S rRNA, and serum and lung metabolites were analyzed by metabolomics. Finally, proteomics was applied to enrich key signaling pathways, and western blot was used to validate the relevant proteins. RESULTS: Fifty-five active components in CY were identified. The pharmacological results showed that CY significantly alleviated lung pathological injury and inflammatory response of lung tissue in ALI mice while improving the integrity of intestinal structure and the permeability of the mucosal barrier in ALI mice. The evaluation was based on the improvement of abnormal expression of inflammatory factors, oxidative stress factors, tight junction proteins, goblet cells, LPS, secretory immunoglobulin A (SIgA), diamine oxidase (DAO), and D-lactic acid (D-LA), to a certain extent. Furthermore, 16S rRNA and metabolomics results showed that multiple core bacterial genera and unsaturated fatty acids were involved during CY treatment. Finally, proteomic results indicated that the Wnt/β-catenin pathway was the mechanism of action for CY treatment of ALI, and CY effectively regulated the protein levels of Wnt3a, β-catenin, and phosphorylated glycogen synthase kinase-3β (p-GSK3β). CONCLUSION: This study confirmed that CY could exert pharmacological effects on improving ALI mice through the gut-lung axis and also found that core bacterial genera and unsaturated fatty acids were involved in this process. More importantly, the Wnt/β-catenin signaling pathway had been identified as a key signaling pathway for CY to alleviate ALI.