Gardenia Iridoid Glucosides Protect Against α-Naphthalene Isothiocya-Nate-Induced Cholestatic Rats Through Activation of the FXR-SHP Signaling Pathway

Abstract

Introduction

Cholestasis is a common liver disorder that currently has limited treatment options. Gardenia Iridoid Glucosides (GIG) have been found to possess various physiological activities, such as cholagogic, hypoglycemic, antibacterial, and anti-inflammatory effects. The objective of this study was to investigate the effects of GIG on bile acid enterohepatic circulation and explore the underlying mechanism in cholestatic rats.

Methods

In order to identify key pathways associated with cholestasis, we conducted Gene Ontology (GO) Enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. In vivo experiments were then performed on alpha-naphthylisothiocyanate (ANIT)-treated rats to assess the impact of GIG. We measured bile flow and various biomarkers including total bilirubin (TB), total bile acids (TBA), total cholesterol (TC), malondialdehyde (MDA), glutamic-pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), and total superoxide dismutase (T-SOD) in the serum. We also examined the expression levels of bile salt export pump (BSEP), ATP-binding cassette subfamily B member 4 (ABCB4), far-nesoid X receptor (FXR), small heterodimer partner (SHP), cholesterol 7α-hydroxylase (CYP7A1), and sodium taurocholate cotransporting polypeptide (NTCP) in liver tissue. In vitro experiments were conducted on primary hepatocytes to further investigate the mechanism of action of GIG on the expression of SHP, CYP7A1, NTCP, and FXR.

Results

Our in vivo experiments demonstrated that GIG significantly increased bile flow and reduced the levels of TB, TBA, TC, MDA, GPT, and GOT, while increasing T-SOD levels in ANIT-treated rats. Addi-tionally, GIG ameliorated liver tissue damage induced by ANIT, upregulated the expression of BSEP and ABCB4, and modulated the protein expression of FXR, SHP, CYP7A1, and NTCP in model rats. In vitro experiments further revealed that GIG inhibited the expression of SHP, CYP7A1, and NTCP by suppressing the expression of FXR.

Conclusion

This study provides new insights into the therapeutic potential of GIG for the treatment of cholestasis. GIG demonstrated beneficial effects on bile acid enterohepatic circulation and liver biomarkers in cholestatic rats. The modulation of FXR and its downstream targets may contribute to the mechanism of action of GIG. These findings highlight the potential of GIG as a therapeutic intervention for cholangitis.

Keywords:

• Gardenia Iridoid Glucosides
• FXR
• SHP
• cholestasis

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

Meng Xu, Ke Che, and Cong Wang are co-first authors for this study. The authors report no conflicts of interest in this work.

Additional information

Funding

This study was supported by the Project of Natural Science Foundation of Anhui Province (2008085QH395), the major natural science research projects in Anhui Universities (KJ2020ZD011), the Anhui province university outstanding young talent support project (Gxyq2021198), research and development of a feed additive for respiratory diseases and immune enhancement in broilers (horizontal cooperation project: 881383),research on the development of antioxidant functional tea and B2C operation mode technology (horizontal cooperation project: 881384).