This study explores the effects and mechanisms of Modified Xiaoyao Powder on the intestinal barrier and intestinal flora in mice with metabolic associated fatty liver disease(MAFLD) based on the " gut-liver axis". Sixty male C57BL/6 mice were randomly divided into the normal group, model group, bifidobacterium tetrad tablet group(SQ), and Modified Xiaoyao Powder groups with low,medium and high doses(XL, XM, XH), with 10 mice in each group. All the mice were administrated with a high-fat diet to build the MAFLD model except the normal group and then treated with related drugs for 12 weeks. Body mass, liver wet weight, and liver index were detected. Serum aspartate aminotransferase(AST), alanine aminotransferase(ALT), total cholesterol(TC), triacylglycerol(TG), low density lipoprotein cholesterol(LDL-C), high density lipoprotein cholesterol(HDL-C), and lipopolysaccharide(LPS)levels were detected using the biochemical kits. The contents of tumor necrosis factor-α(TNF-α) and interleukin(IL-6) in the liver were tested simultaneously. The morphological changes of the liver and intestine were observed using hematoxylin-eosin(HE) staining and oil red O staining. The goblet cells in the ileum were detected by periodic acid Schiff and alcian blue stain(AB-PAS) staining.The expression of zonula occludens-1(ZO-1), recombinant occludin(occludin), and recombinant claudin 1(claudin-1) in ileum and colon were detected by immunohistochemistry and Western blot. The changes of intestinal flora in mice were analyzed by 16S rRNA gene sequencing. The results showed that compared with the normal group, body weight, liver wet weight and liver index in the model group increased. The contents of TC, TG, ALT, AST, LDL-C, and LPS in the serum of the model group increased, while HDL-C decreased. Meanwhile, the contents of TNF-α and IL-6 in liver tissue increased and liver lipid accumulation increased, indicating successful model induction. Compared with the model group, body weight, liver wet weight, and liver index were decreased in XM,XH groups and SQ group. Serum levels of TC, TG, LDL-C, ALT and AST in XM group and SQ group were significantly decreased,and HDL-C levels were increased. The levels of IL-6, TNF-α in liver tissue and serum LPS in the XL, XM groups and SQ group were significantly decreased. The protein expression of claudin-1, occludin and ZO-1 in XL, XM groups and SQ group were increased. The analysis of intestinal flora showed that compared with the model group, Modified Xiaoyao Powder with a medium dose could significantly improve the richness and diversity of intestinal flora in mice. At the phylum level, the Firmicutes/Bacteroidetes(F/B) ratio decreased; at the genus level, Lactobacillus, Brautella, Bacteroides, and Ackermannia increased, while Prevotella, Desulfovibrio and Turicibacter decreased. The main differential species were Odorbacteraceaeae and Peptostreptococcaceae. In conclusion, Modified Xiaoyao Powder could inhibit inflammation, regulate intestinal flora homeostasis, and promote the repair of the intestinal mucosal barrier in mice with MAFLD.
Keywords: Modified Xiaoyao Powder; gut-liver axis; intestinal flora; intestinal mucosal barrier; metabolic associated fatty liver disease.