Xiaoyao powder attenuates acetaminophen-induced liver injury through modulating gut microbiota and upregulating GLYAT

Xiaoyao Powder (XYP) is a traditional Chinese medicine formula first recorded in the Tai Ping Hui Min He Ji Ju Fang. It has been used for over 900 years to treat "liver depression and spleen deficiency" syndrome. Acute drug-induced liver injury (DILI) often presents clinical features analogous to "liver depression and spleen deficiency" syndrome.

This study aimed to explore the intestinal mechanism of XYP for treating DILI.

An acetaminophen (APAP)-induced DILI mouse model was established to validate the efficacy of XYP. Levels of aspartate transaminase (AST) and alanine aminotransferase (ALT) were measured, and hematoxylin-eosin (H&E) staining was performed. Subsequently, 16S rRNA gene sequencing and real-time PCR were used to investigate the role of gut microbiota during XYP treatment. In addition, intestinal pseudo-germ-free mouse models were established by antibiotic cocktail (ATB) administration to verify the mechanism of XYP. Intestinal barrier integrity was assessed via histological staining (H&E and periodic acid-Schiff (PAS)), immunohistochemical detection of zonula occludens-1 (ZO-1) and occludin, and measurement of serum lipopolysaccharide (LPS) and diamine oxidase (DAO) levels. Liver glycine-N-acyltransferase (GLYAT) expression was evaluated by Western blotting. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze the components in serum, liver tissues, and XYP decoction.

XYP alleviated APAP-induced liver injury in mice in a dose-dependent manner. In the medium-dose XYP (M-XYP) group (ALT: 27.63 ± 0.59 U/L; AST: 35.42 ± 2.93 U/L), ALT and AST activities decreased by 65 % and 70 %, respectively, compared to the model group (ALT: 78.96 ± 1.51 U/L; AST: 118.89 ± 1.66 U/L) (P = 0.01). XYP mitigated APAP-induced disturbances in gut microbiota composition, increased gut microbiota diversity, and elevated the abundance of Lactobacillus acidophilus. Notably, XYP improved liver injury and intestinal barrier function by increasing L. acidophilus abundance. Metabolically, XYP decoction enhanced amino acid metabolism in DILI mice. Compared with ATB-treated DILI mice, XYP elevated serum hippuric acid levels in specific pathogen-free (SPF) DILI mice. L. acidophilus was essential for XYP-mediated upregulation of GLYAT in the liver. Mechanistically, L. acidophilus cooperated with XYP to promote hepatic GLYAT expression in DILI mice.

XYP alleviated APAP-induced liver injury in mice by increasing L. acidophilus abundance. Notably, L. acidophilus upregulated hepatic GLYAT expression and enhanced intestinal barrier function. These findings provide a potential therapeutic strategy combining XYP with L. acidophilus for managing DILI.