Mechanisms of the Anti-Fibrotic Effect of Ginsenoside Rh1 on Hepatic Fibrosis

Abstract

To investigate whether ginsenoside Rh1 (G-Rh1) can alleviate liver fibrosis induced by a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) and to explore its underlying mechanisms.

Methods  Male C57BL/6J mice were randomly divided into 6 groups (n = 8 in each group), including a standard diet group (or the control group), a high-fat diet group (or the CDAHFD group), a silymarin group (given silymarin at 5 mg/kg), a low-dose G-Rh1 group (given G-Rh1 at 5 mg/kg), a medium-dose G-Rh1 group (given G-Rh1 at 10 mg/kg), and a high-dose G-Rh1 group (given G-Rh1 at 20 mg/kg). The control group was given a standard feed, while the other groups were fed CDAHFD for 7 weeks to establish the mouse model of liver fibrosis. Starting from the first week, the mice in the treatment groups were administered the corresponding drugs by intragastric gavage once daily for 7 weeks in succession. After the administration of the final drug treatment, the body mass and organ mass of the mice in different groups were measured, and the organ index was obtained according. Liver tissues were examined using HE staining, Sirius red staining, and immunohistochemistry (IHC) staining. Western blot was performed to measure α-smooth muscle actin (α-SMA) and transforming growth factor-β1 (TGF-β1), two liver fibrosis-related proteins, and fibroblast growth factor 12 (FGF-12), a pathway-related protein. The serum biochemical indicators, including aspartate transferase (AST), alanine aminotransferase (ALT), total bilirubin (TBIL), and direct bilirubin (DBIL), were measured. Additionally, RAW246.7 cells were randomly divided into 5 groups, including a control group, a lipopolysaccharide (LPS) group, and 3 G-Rh1 treatment groups. The control group had only RAW246.7 cells in the culture medium. The other groups were given LPS (500 ng/mL), and the 3 treatment groups received G-Rh1 at 10, 20, and 40 μmol/L in addition. The supernatants from the 5 groups of RAW246.7 cells were collected and cocultured with HSC-T6 cells for 24 hours to observe and compare the effects of G-Rh1 and LPS on the expression of fibrosis-related proteins, including α-SMA, Col1a1, etc, in HSC-T6 cells and on the expression of fibrotic signaling pathway-related proteins, including fibroblast growth factor 12 (FGF-12) and signal transducer and activator of transcription 3 (STAT3)/phosphorylated STAT3 (p-STAT3), in RAW264.7 cells. Flow cytometry was conducted to analyze the phenotypes of RAW246.7 cells, and ELISA was performed to measure fibrosis-related factors, including monocyte chemoattractant protein-1 (MCP-1) and transforming growth factor-β (TGF-β).

Results  Compared with the control mice, the mice in the CDAHFD group exhibited obvious liver fibrosis. Compared with CDAHFD mice, mice in the G-Rh1 treatment groups all showed alleviation of liver fibrosis of was alleviated to some extent in a dose-dependent manner, and the improvement effect was superior to that of silymarin, a reference drug. G-Rh1 also alleviated CDAHFD-induced body mass loss (P < 0.01), reduced the liver index (P < 0.01), and significantly decreased the serum levels of AST, ALT, DBIL, and TBIL (P < 0.0001). Significant differences in the protein expression of α-SMA, TGF-β1, and FGF-12 in the liver were observed (P < 0.01). Compared with the LPS group, the LPS + G-Rh1 groups exhibited significant differences in the expression of FGF-12 and p-STAT3/STAT3 in RAW246.7 cells, and α-SMA and Col1a1 in HSC-T6 cells (P < 0.001). In the LPS + G-Rh1 groups (the 20 μmol/L and 40 μmol/L treatment groups), the conversion ratio of Ly6C-low expressing RAW246.7 cells into Ly6C-high expressing RAW246.7 cells decreased significantly (P < 0.0001), while the secretion of fibrosis-related factors MCP-1 and TGF-β decreased (P < 0.0001), which was consistent with the trend of the activation levels of HSC-T6 cells.

Conclusions  G-Rh1 can prevent and improve CDAHFD-induced liver fibrosis in mice, potentially through mechanisms involving the reduction of RAW264.7 phenotype transformation mediated by FGF-12 overexpression.

Keywords: Ginsenoside Rh1, Liver fibrosis, Macrophage, Hepatic stellate cells, FGF-12