Objective To investigate the microbial mechanisms of Banxia Xiexin Decoction (半夏泻心汤, BXXXD) in the treatment of esophageal precancerous lesions.

Methods A total of 30 specific pathogen-free (SPF) grade female C57BL/6J mice were randomly assigned to a control group (n = 6) and a 4-nitroquinoline 1-oxide (4-NQO)-exposed group (n = 24). Esophageal precancerous lesions were induced by providing the 4-NQO-exposed group with 4-NQO in drinking water (100 μg/mL) for 17 consecutive weeks, whereas control group received sterile drinking water. After model establishment, the mice in 4-NQO-exposed group were further randomized into model group and three BXXXD-treated groups: low-dose (BXXXD-L, 3.7 g/kg), medium-dose (BXXXD-M, 7.4 g/kg), and high-dose (BXXXD-H, 14.8 g/kg) groups (n = 6 per group). During the subsequent intervention period, mice in control and model groups were gavaged with sterile water, while mice in BXXXD groups were gavaged once daily with the corresponding dose of BXXXD aqueous extract for 4 weeks. Histopathological changes in esophageal tissues were observed by hematoxylin and eosin (HE) staining. The fecal and esophageal microbiota were profiled via 16S rDNA high-throughput sequencing to evaluate bacterial diversity, community structure, and co-occurrence networks. BXXXD chemical fingerprints were analyzed using ultra-high-performance liquid chromatography coupled with quadrupole QExactive Orbitrap mass spectrometry (UHPLC-QE-MS). Serum short-chain fatty acids (SCFA) level was quantified by targeted metabolomics using gas chromatography-mass spectrometry (GC-MS). Transcriptomic analysis of esophageal tissues was performed to assess gene expression profiles.

Results Compared with model group, BXXXD-M group exhibited reduced mucosal hyperplasia and more orderly epithelial cell arrangement, with superior therapeutic effects in comparison with both BXXXD-L and BXXXD-H groups (P < 0.01). Microbiota analysis revealed that BXXXD increased the abundance of beneficial Enterococcus and reduced pathogenic Escherichia-Shigella in the esophagus. In the gut, BXXXD elevated the relative abundance of beneficial taxa, including Lactobacillus, Dubosiella, Bacteroides, and Faecalibacterium. Targeted metabolomics showed that BXXXD significantly reduced total serum SCFA level (P < 0.01). Transcriptomic analysis indicated that BXXXD downregulated the expression of genes associated with the progression, migration, and invasion of esophageal cancer, which were identified as kallikrein-related peptidase 6 (Klk6), defensin beta 4 (Defb4), family with sequence similarity 3 member B (Fam3b), carboxypeptidase A4 (Cpa4), serum amyloid A1 (Saa1), and chitinase-like 1 (Chil1) (P < 0.05).

Conclusion BXXXD may reduce the expression levels of esophageal cancer-related genes and improve esophageal precancerous lesions through modulation of the gut microbiota and metabolites.