AUTHOR=Zhu Lingping , Li Duo , Yang Xuefeng 

TITLE=Gut metabolomics and 16S rRNA sequencing analysis of the effects of arecoline on non-alcoholic fatty liver disease in rats

JOURNAL=Frontiers in Pharmacology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2023.1132026

DOI=10.3389/fphar.2023.1132026

ISSN=1663-9812

ABSTRACT=<p><bold>Introduction:</bold> Non-alcoholic fatty liver disease (NAFLD) has gradually become the primary cause of fatty liver disease. Betel nuts have been used to treat gastrointestinal diseases.</p><p><bold>Methods:</bold> In the present study, we analyzed the pathology, serology, gut flora, and metabolites in a rat model of NAFLD, with and without betel nut alkaloid treatment, using an integrated approach involving pathology, serological testing, 16S rRNA gene sequencing, and ultra-performance liquid chromatography-mass spectrometry metabolomics.</p><p><bold>Results:</bold> Two rats were used for model validation. Thirty SD rats were included and divided into the normal group (C group), NAFLD model group (M group), low-dose group, medium-dose group (T group), and high-dose group with intraperitoneal injection of arecoline. The expression of blood lipids was significantly downregulated at all three arecoline concentrations (<italic>p</italic> &lt; 0.05). Alpha-diversity analysis of the intestinal flora showed significant differences among the three groups, with a significant reduction in population diversity in the M group and a recovery of population diversity after arecoline treatment. At the phylum level, the relative abundance of <italic>Firmicutes</italic> was significantly higher in the T group and <italic>Proteobacteria</italic> in the M group. The KEGG metabolic pathways included polyketide sugar unit biosynthesis and hypertrophic cardiomyopathy. Thirty-three significantly different metabolites were identified among the groups. Significantly different metabolites between groups T and M included indolepyruvate, 2-deoxystreptamine, sakuranetin, glycyl-leucine, and riboflavin. The KEGG metabolic pathway suggested a potential role for arachidonic acid metabolism, serotonergic synapses, neuroactive ligand-receptor interactions, tyrosine metabolism, and regiomelanin. Vitamin digestion and absorption, as well as regulation of lipolysis in adipocytes, were the main metabolic pathways that distinguished the T vs. M groups. PGE2 is involved in several metabolic pathways. Correlation analysis showed that 29 bacterial species were significantly associated with PGE2 levels in the M and T groups. <italic>Vagococcus</italic>, <italic>Lawsonia</italic>, <italic>Christensenella</italic>, unidentified <italic>Erysipelotrichaceae</italic>, unidentified <italic>Coriobacteriaceae</italic>, and five other bacterial groups are unique in the PGE2 metabolic pathway regulated by arecoline.</p><p><bold>Discussion:</bold> Arecoline has lipid-lowering effects and may exert therapeutic effects in NAFLD through intestinal metabolites and intestinal flora, as well as through the <italic>Butyricicoccus</italic>/<italic>Christensenella</italic>/<italic>Coriobacteriaceae</italic>-COX2/PGE2 pathway. Thus, arecoline may represent a potential drug or target for NAFLD treatment.</p>