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人参皂苷Rh1抗肝纤维化的作用机制研究

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

  • 摘要:
    目的 研究稀有人参皂苷Rh1(ginsenoside Rh1, G-Rh1)是否可以降低由胆碱缺乏,L-氨基酸缺乏的高脂饮食(choline-deficient, L-amino acid-defined, high-fat diet, CDAHFD)诱导的肝纤维化,并探讨其可能存在机制。
    方法 将雄性C57BL/6J小鼠随机分为标准饲料组(Control组)、高脂饲料组(CDAHFD组)、水飞蓟素组(Silymarin,5 mg/kg)、G-Rh1低剂量组(5 mg/kg)、G-Rh1中剂量组(10 mg/kg)、G-Rh1高剂量组(20 mg/kg),每组8只。Control组正常喂养,其余小组均以CDAHFD连续喂养7周建立小鼠肝纤维化模型;于第一周起,各给药组小鼠分别灌胃相应药液,每天1次,连续7周。末次给药后,称定各组小鼠体质量、脏器质量并得出脏器指数;HE染色、天狼星红染色和免疫组织化学染色(IHC)观察肝脏组织;Western blot检测肝纤维化相关蛋白α-平滑肌肌动蛋白(α-SMA)、转化生长因子-β1(TGF-β11,通路相关蛋白成纤维细胞生长因子12( FGF-12);检测血清生化指标天冬氨酸转移酶(AST)、丙氨酸转氨酶(ALT)、总胆红素(TBIL)和直接胆红素(DBIL)。将小鼠巨噬细胞(RAW246.7)随机分为5组〔对照组、脂多糖(LPS)组、3个给药组〕。除对照组RAW246.7细胞只含有RAW246.7细胞和培养基外,其余组RAW246.7细胞均加入培养基、RAW246.7细胞和LPS(终浓度500 ng/mL),3个给药组在此基础上分别加入10 μmol/L、20 μmol/L、40 μmol/L G-Rh1。取5组RAW264.7细胞的上清液与大鼠肝星状细胞(HSC-T6)共培养24 h,观察比较G-Rh1或LPS对HSC-T6中α-SMA、Ⅰ-a1型胶原蛋白(Col1a1)等纤维化相关蛋白,及对RAW264.7中FGF-12和p-STAT3/STAT3纤维化信号通路相关蛋白表达的影响;流式分析检测RAW264.7表型;ELISA检测促纤维化因子单核细胞趋化蛋白1(MCP-1)和TGF-β。
    结果 与正常Control组比较,CDAHFD组小鼠明显出现肝纤维化。与CDAHFD小鼠比较,G-Rh1给药组小鼠肝纤维化均有一定缓解,存在剂量依赖相关性,且缓解效果优于对照药物水飞蓟素;同时,G-Rh1可缓解CDAHFD导致的体质量下降(P<0.01),降低肝脏指数(P<0.01),血清AST、ALT、DBIL和TBIL含量显著下降(P<0.0001),肝脏中α-SMA、TGF-β1和FGF-12蛋白表达差异均有统计学意义(P<0.01)。与LPS组相比,LPS+G-Rh1各组RAW264.7中FGF-12和p-STAT3/STAT3, HSC-T6中α-SMA和Col1a1的表达差异有统计学意义(P<0.001);LPS+G-Rh1(20 μmol/L、40 μmol/L)组中Ly6C低表达RAW264.7向Ly6C高表达的转化比例显著降低(P<0.0001),同时促纤维化因子MCP-1和TGF-β分泌减少(P<0.0001),与HSC-T6的激活程度趋势一致。
    结论 G-Rh1可预防改善CDAHFD诱导的小鼠肝纤维化,其机制可能与降低FGF-12过表达介导的RAW264.7表型转化相关。

     

    Abstract:
    Objective  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.

     

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