ABSTRACT
In this study, the mechanism of Xiaoyan Lidan formula (XYLDF) against 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-collidine (DDC)-induced chronic intrahepatic cholestasis (CIHC) in mice was investigated based on metabolomics, molecular docking and pharmacological methods. In the pharmacodynamics study, a dosage of 5 g·kg-1 (clinical equivalent) XYLDF was administered in DDC-induced mice, then the effect of XYLDF against CIHC was evaluated by measuring the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP) as well as total bilirubin (TBIL) in serum and observing liver histopathological changes. All experiments were approved by the Ethical Committee Experimental Animal Center of Guangzhou University of Chinese Medicine (ZYD-2021-001). The serum metabolites of mice in each group were detected and identified based on ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry, and the relevant biological pathways and molecular key targets were further enriched. Molecular docking technology was used to further evaluate the binding activity of the main active ingredients of XYLDF with potential targets. Subsequently, the in vitro experiment was conducted for the validation of the vital target. The results showed that compared with the model group, XYLDF significantly decreased the levels of ALT, AST, AKP and TBIL in the serum of CIHC mice, as well as alleviated inflammatory infiltration and hepatocyte necrosis in liver tissue. According to the metabonomic study, a total of 35 differential metabolites was identified as biomarkers associated with cholestasis, 12 of which were significantly recovered by XYLDF treatment. These biomarkers were involved in the pathways of primary bile acid biosynthesis and linoleic metabolism, which are closely related to the mechanism of XYLDF against CIHC. Protein-protein interaction network indicated that cytochrome P450 3A4 (CYP3A4) and cytochrome P450 1A1 (CYP1A1) are significant potential targets with good binding properties with six major active ingredients of XYLDF. Furthermore, it was found that 4-methoxy-5-hydroxycanthin-6-one, dehydroandrographolide and isodocarpin, three of the main active components in XYLDF, markedly induced the expression of CYP3A4 mRNA in vitro. This study revealed that XYLDF mainly mediates the biosynthesis of bile acids in CIHC mice to improve liver tissue lesions and bile efflux disorders, among which, CYP3A4 is the key target in the protection of XYLDF against CIHC. This research provides a reference for further elucidation of the pharmacological mechanism of XYLDF.