Integrated Metabolomic and Gut Microbiome Analyses Reveal the Therapeutic Effects of Xuanfei Heji in Rats With Chronic Obstructive Pulmonary Disease

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a leading cause of death, underscoring the need for improved therapies. Xuanfei Heji (XFHJ), a hospital-prepared herbal formula, has been used clinically in the treatment of COPD. However, its mechanisms remain unclear. METHODS: XFHJ constituents were profiled using UHPLC-HRMS. COPD was induced in rats by intratracheal lipopolysaccharide instillation and cigarette smoke exposure. Treatment effects were assessed using pulmonary function, lung histopathology, and proinflammatory cytokines. Untargeted serum metabolomics and fecal 16S rRNA gene sequencing were performed; associations among differential metabolites, microbial taxa, and inflammatory markers were evaluated using Spearman's rank correlation analysis. RESULTS: Chemical profiling tentatively identified 374 constituents. XFHJ improved pulmonary function and attenuated lung histopathological injury and inflammation. Tryptophan and glycerophospholipid metabolism were the principal treatment-associated pathways. XFHJ also altered gut microbial diversity and composition, with enrichment of potentially beneficial taxa such as Bifidobacterium, Roseburia, and several Clostridia-related taxa. Treatment-responsive taxa correlated positively with indole-related metabolites, which correlated inversely with pulmonary inflammatory markers. CONCLUSIONS: XFHJ exhibited significant therapeutic effects on COPD rats, and its mechanism may be correlated with regulating the intestinal microbiota structure and metabolic profiles of COPD rats, thereby attenuating lung histopathological injury and pulmonary inflammation.