The effects of Atractylodes macrocephala extract BZEP self-microemulsion based on gut-liver axis HDL/LPS signaling pathway to ameliorate metabolic dysfunction-associated fatty liver disease in rats

Abstract

Objectives: To elucidate the therapeutic effects and mechanisms of Atractylodes macrocephala extract crystallize (BZEP) and BZEP self-microemulsion (BZEPWR) on metabolic dysfunction-associated fatty liver disease (MAFLD) induced by "high sugar, high fat, and excessive alcohol consumption" based on the gut-liver axis HDL/LPS signaling pathway.

Methods: In this study, BZEP and BZEPWR were obtained via isolation, purification, and microemulsification. Furthermore, an anthropomorphic MAFLD rat model of "high sugar, high fat, and excessive alcohol consumption" was established. The therapeutic effects of BZEPWR and BZEP on the model rats were evaluated in terms of liver function, lipid metabolism (especially HDL-C), serum antioxidant indexes, and liver and intestinal pathophysiology. To determine the lipoproteins in the serum sample, the amplitudes of a plurality of NMR spectra were derived via deconvolution of the composite methyl signal envelope to yield HDL-C subclass concentrations. The changes in intestinal flora were detected via 16 S rRNA gene sequencing. In addition, the gut-liver axis HDL/LPS signaling pathway was validated using immunohistochemistry, immunofluorescence, and western blot.

Results: The findings established that BZEPWR and BZEP improved animal signs, serum levels of liver enzymes (ALT and AST), lipid metabolism (TC, TG, HDL-C, and LDL-C), and antioxidant indexes (GSH, SOD, and ROS). In addition, pathological damage to the liver, colon, and ileum was ameliorated, and the intestinal barrier function of the model rats was restored. At the genus level, BZEPWR and BZEP exerted positive effects on beneficial bacteria, such as Lactobacillus and norank_f__Muribaculaceae, and inhibitory effects on harmful bacteria, such as unclassified_f__Lachnospiraceae and Blautia. Twenty HDL-C subspecies were detected, and their levels were differentially increased in both BZEPWR and BZEP groups, with BZEPWR exhibiting a stronger elevating effect on specific HDL-C subspecies. Also, the gut-liver axis HDL/LPS signaling pathway was studied, which indicated that BZEPWR and BZEP significantly increased the expressions of ABCA1, LXR, occludin, and claudin-1 proteins in the gut and serum levels of HDL-C. Concomitantly, the levels of LPS in the serum and TLR4, Myd88, and NF-κB proteins in the liver were decreased.

Conclusion: BZEPWR and BZEP exert restorative and reversal effects on the pathophysiological damage to the gut-liver axis in MAFLD rats, and the therapeutic mechanism may be related to the regulation of the intestinal flora and the HDL/LPS signaling pathway.

Keywords: Atractylodes macrocephala extract; Atractylodes macrocephala extract crystallize self-microemulsion (BZEPWR); Gut-liver axis; HDL/LPS signalling pathway; Metabolic dysfunction-associated fatty liver disease (MAFLD).