Structural and Functional Modulation of Gut Microbiota by Jiangzhi Granules during the Amelioration of Nonalcoholic Fatty Liver Disease

Abstract

Recently, accumulating evidence revealed that nonalcoholic fatty liver disease (NAFLD) is highly associated with the dysbiosis of gut microbiota. Jiang Zhi Granule (JZG), which is composed of five widely used Chinese herbs, has shown hypolipidemic effect, while whether such effect is mediated by gut microbiota is still unclear. Here, we found that both low and high doses of JZG (LJZ and HJZ) could improve hepatic steatosis and function, as well as insulin resistance in NAFLD mice. 16S rRNA gene sequencing revealed that JZG treatment could reverse the dysbiosis of intestinal flora in NAFLD mice, exhibiting a dose-dependent effect. Notably, HJZ could significantly reduce the relative abundance of Desulfovibrionaceae, while increasing the relative abundance of such as S24_7 and Lachnospiraceae. PICRUSt analysis showed that HJZ could significantly alter the functional profile of gut microbiota, including the reduction of the lipopolysaccharide biosynthesis and sulfur metabolism pathway, which is verified by the decreased levels of fecal hydrogen sulfide (H2S) and serum lipopolysaccharide binding protein (LBP). In addition, hepatic mRNA sequencing further indicated that the HJZ group can regulate the peroxisome proliferator-activated receptor (PPAR) pathway and inflammatory signaling pathway, as validated by RT-PCR and Western blot. We also found that different doses of JZG may regulate lipid metabolism through differentiated pathways, as LJZ mainly through the promotion of hepatic lipid hydrolysis, while HJZ mainly through the improvement of hepatic lipid oxidation. Taken together, JZG could modulate gut dysbiosis with dose-effect, alleviate inflammation level, and regulate hepatic lipid metabolism, which may subsequently contribute to the improvement of NAFLD. Our study revealed the underlying mechanisms in the improvement of NAFLD by a Chinese herbal compound, providing future guidance for clinical usage.