ABSTRACT
Objective:To investigate the effects and mechanisms of Yinzhihuang oral liquid on mice with high-fat diet induced non-alcoholic fatty liver disease (NAFLD).Methods:Eighteen C57BL/6J female mice were divided into normal diet group, high-fat diet group and Yinzhihuang oral liquid group, with six mice in each group. After hematoxylin-eosin staining, oil red O staining and Masson staining, pathological scores of liver biopsy slices were calculated. Plasma levels of triacylglycerol, total cholesterol, total bilirubin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested. The composition of bile acid in mouse ileum content were measured by high performance liquid chromatography-tandem mass spectrometry, which included tauro-β-muricholic acid (TβMCA), ursodeoxycholic acid (UDCA) and cholic acid. The expression of farnesoid Ⅹ receptor ( FXR), fibroblast growth factor 15 ( FGF15), fibroblast growth factor receptor 4 ( FGFR4) genes at mRNA and protein levels and cytochrome P450 (CYP) 27a1, CYP7b1, CYP7a1 and CYP8b1 were detected by real-time quantitative polymerase chain reaction, Western blotting and immunohistochemistry, respectively. T test was used for statistical analysis. Results:The levels of plasma triacylglycerol, total cholesterol, total bilirubin, ALT and AST of Yinzhihuang oral liquid group were all lower than those of the high-fat diet group ((1.47±0.07) mmol/L vs. (1.90±0.13) mmol/L, (2.57±0.17) mmol/L vs. (6.84±0.23) mmol/L, (0.88±0.22) mg/dL vs. (2.06±0.25) mg/dL, (28.43±3.16) U/L vs. (87.15±23.27) U/L, (147.40±8.47) U/L vs. (289.00±12.66) U/L, respectively), and the differences were statistically significant ( t=3.90, 15.19, 4.31, 2.50 and 9.58, all P<0.05). The scores of adiposis and ballooning of hepatocytes of Yinzhihuang oral liquid group were lower than those of the high-fat diet group (1.00±0.26 vs. 2.33±0.33, 0.33±0.21 vs. 1.17±0.31, respectively), and the differences were all statistically significant ( t=3.90 and 4.90, both P<0.05). The levels of FXR antagonistic bile acids TβMCA and UDCA in ileal contents of Yinzhihuang oral liquid group were both higher than those of high-fat diet group ((4.95±0.68) nmol/g vs. (2.64±0.15) nmol/g, (7.86±1.84) nmol/g vs. (2.22±0.38) nmol/g, respectively), and the differences were statistically significant ( t=3.92 and 2.99, both P<0.05). The level of FXR agonistic bile acid cholic acid of Yinzhihuang oral liquid group were lower than that of the high-fat diet group ((4.69±0.46) nmol/g vs. (21.66±3.25) nmol/g), and the difference was statistically significant ( t=5.14, P<0.05). The expression of FXR, FGF15 in ileal tissues and FGFR4 in hepatic tissues at mRNA and protein levels of Yinzhihuang oral liquid group were all lower than those of the high-fat diet group (1.86±0.40 vs. 4.25±0.70, 9.99±2.82 vs. 75.17±23.41, 4.76±0.63 vs. 12.66±1.39, 2.20±0.14 vs. 5.30±0.25, 1.15±0.05 vs. 3.05±0.16 and 1.73±0.09 vs. 2.37±0.21, respectively), and the differences were statistically significant ( t=2.56, 2.76, 4.87, 10.90, 10.96 and 2.94, all P<0.05). The levels of CYP27a1 and CYP7b1 in the alternative pathway of bile acid synthesis in Yinzhihuang oral liquid group were both higher than those in the high-fat diet group (2.13±0.33 vs. 0.50±0.09 and 2.95±0.60 vs. 0.37±0.19), and the differences were statistically significant ( t=5.22 and 3.20, both P<0.05). But the expression level of CYP8b1 in the Yinzhihuang oral liquid group was lower than that in the high-fat diet group (2.38±0.41 vs. 8.63±2.20), and the difference was statistically significant ( t=2.80, P<0.05). Conclusion:Yinzhihuang oral liquid can reduce NAFLD by promoting bile acid synthesis through changing the components of intestinal bile acids in mice and inhibiting FXR-FGF15 signal pathway.