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Nrf2 pathway activation contributes to anti-fibrosis effects of ginsenoside Rg1 in a rat model of alcohol- and CCl4-induced hepatic fibrosis.

Li JP, Gao Y, Chu SF, Zhang Z, Xia CY, Mou Z, Song XY, He WB, Guo XF, Chen NH - Acta Pharmacol. Sin. (2014)

Bottom Line: Rg1 significantly increased the activities of antioxidant enzymes (SOD, GSH-Px and CAT) and reduced MDA levels in liver tissues.Furthermore, Rg1 significantly increased the expression and nuclear translocation of Nrf2 that regulated the expression of many antioxidant enzymes.Knockdown of Nrf2 gene diminished these actions of Rg1 in CCl4-treated HSCs in vitro.

View Article: PubMed Central - PubMed

Affiliation: State Key of Laboratory Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.

ABSTRACT

Aim: To investigate the anti-fibrosis effects of ginsenoside Rg1 on alcohol- and CCl4-induced hepatic fibrosis in rats and to explore the mechanisms of the effects.

Methods: Rats were given 6% alcohol in water and injected with CCl4 (2 mL/kg, sc) twice a week for 8 weeks. Rg1 (10, 20 and 40 mg/kg per day, po) was administered in the last 2 weeks. Hepatic fibrosis was determined by measuring serum biochemical parameters, HE staining, Masson's trichromic staining, and hydroxyproline and α-SMA immunohistochemical staining of liver tissues. The activities of antioxidant enzymes, lipid peroxidation, and Nrf2 signaling pathway-related proteins (Nrf2, Ho-1 and Nqo1) in liver tissues were analyzed. Cultured hepatic stellate cells (HSCs) of rats were prepared for in vitro studies.

Results: In the alcohol- and CCl4-treated rats, Rg1 administration dose-dependently suppressed the marked increases of serum ALT, AST, LDH and ALP levels, inhibited liver inflammation and HSC activation and reduced liver fibrosis scores. Rg1 significantly increased the activities of antioxidant enzymes (SOD, GSH-Px and CAT) and reduced MDA levels in liver tissues. Furthermore, Rg1 significantly increased the expression and nuclear translocation of Nrf2 that regulated the expression of many antioxidant enzymes. Treatment of the cultured HSCs with Rg1 (1 μmol/L) induced Nrf2 translocation, and suppressed CCl4-induced cell proliferation, reversed CCl4- induced changes in MDA, GPX, PCIII and HA contents in the supernatant fluid and α-SMA expression in the cells. Knockdown of Nrf2 gene diminished these actions of Rg1 in CCl4-treated HSCs in vitro.

Conclusion: Rg1 exerts protective effects in a rat model of alcohol- and CCl4-induced hepatic fibrosis via promoting the nuclear translocation of Nrf2 and expression of antioxidant enzymes.

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Effects of Rg1 on liver histology following CCl4 treatment. Rats were subcutaneously injected with CCl4 (0.2 mL/kg BW, twice per week) for 8 weeks, and Rg1 and bicyclol were administered at the last two weeks (once a day). Representative photomicrographs of liver histology (H & E, magnification: ×40) from each group are shown as follows: Control (A), CCl4 alone (B), CCl4+Bicyclol (C), CCl4+Rg1-10 mg/kg (D), CCl4+Rg1-20 mg/kg (E) and CCl4+Rg1-40 mg/kg (F). Scale bar, 100 μm. The inflammatory score (G) and balloon degeneration score (H) were evaluated in ten randomly selected fields from each slide at a magnification of ×200. All data were expressed as mean±SD of six animals. cP<0.01 vs control. fP<0.01 vs CCl4 alone.
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fig1: Effects of Rg1 on liver histology following CCl4 treatment. Rats were subcutaneously injected with CCl4 (0.2 mL/kg BW, twice per week) for 8 weeks, and Rg1 and bicyclol were administered at the last two weeks (once a day). Representative photomicrographs of liver histology (H & E, magnification: ×40) from each group are shown as follows: Control (A), CCl4 alone (B), CCl4+Bicyclol (C), CCl4+Rg1-10 mg/kg (D), CCl4+Rg1-20 mg/kg (E) and CCl4+Rg1-40 mg/kg (F). Scale bar, 100 μm. The inflammatory score (G) and balloon degeneration score (H) were evaluated in ten randomly selected fields from each slide at a magnification of ×200. All data were expressed as mean±SD of six animals. cP<0.01 vs control. fP<0.01 vs CCl4 alone.

Mentions: To determine the protective effects of Rg1 against CCl4-induced injury, we conducted histological examination of the extent of hepatic injury. According to microscopic examination, the administration of Rg1 alleviates severe hepatic lesions induced by alcohol and CCl4. Control rats had no pathological changes in either the lateral or median lobes of the liver (Figure 1A). Rats in the untreated fibrosis group had degenerative changes in the liver: centrilobular necrosis including ballooning of hepatocytes, deposition of lipid droplets in hepatocytes and infiltration of inflammatory cells, as well as collagen deposition17. In rats in the Rg1 10 mg/kg treated group, severe hepatocyte necrosis and ballooning degeneration were observed, as well as numerous inflammatory cells around the necrotic tissue (Figure 1D). Moderate hydropic degeneration of hepatocytes was shown in Rg1 20 mg/kg treated group. In the Rg1 40 mg/kg treated group, hepatocyte necrosis nearly disappeared (Figure 1F), showing a significant reduction in necrosis and hydropic degeneration. The inflammation score of each group was evaluated. As shown in Figure 1G, the inflammation score was 0.18±0.01 in the control group, while in the CCl4 group, the inflammation score was markedly increased (3.17±0.32, P<0.01). In contrast, compared with the untreated fibrosis group, treatment with Rg1 (10, 20, and 40 mg/kg) significantly reduced the increased inflammation scores (2.55±0.33, 2.05±0.19, and 1.62±0.50; P<0.05, P<0.01, and P<0.01, respectively). The balloon degeneration score (Figure 1H) was also significantly reduced by Rg1 (20 mg, 1.95±0.20 and 40 mg, 1.45±0.18; P<0.01, and P<0.01, respectively) compared with rats in the untreated fibrosis group (2.53±0.19).


Nrf2 pathway activation contributes to anti-fibrosis effects of ginsenoside Rg1 in a rat model of alcohol- and CCl4-induced hepatic fibrosis.

Li JP, Gao Y, Chu SF, Zhang Z, Xia CY, Mou Z, Song XY, He WB, Guo XF, Chen NH - Acta Pharmacol. Sin. (2014)

Effects of Rg1 on liver histology following CCl4 treatment. Rats were subcutaneously injected with CCl4 (0.2 mL/kg BW, twice per week) for 8 weeks, and Rg1 and bicyclol were administered at the last two weeks (once a day). Representative photomicrographs of liver histology (H & E, magnification: ×40) from each group are shown as follows: Control (A), CCl4 alone (B), CCl4+Bicyclol (C), CCl4+Rg1-10 mg/kg (D), CCl4+Rg1-20 mg/kg (E) and CCl4+Rg1-40 mg/kg (F). Scale bar, 100 μm. The inflammatory score (G) and balloon degeneration score (H) were evaluated in ten randomly selected fields from each slide at a magnification of ×200. All data were expressed as mean±SD of six animals. cP<0.01 vs control. fP<0.01 vs CCl4 alone.
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fig1: Effects of Rg1 on liver histology following CCl4 treatment. Rats were subcutaneously injected with CCl4 (0.2 mL/kg BW, twice per week) for 8 weeks, and Rg1 and bicyclol were administered at the last two weeks (once a day). Representative photomicrographs of liver histology (H & E, magnification: ×40) from each group are shown as follows: Control (A), CCl4 alone (B), CCl4+Bicyclol (C), CCl4+Rg1-10 mg/kg (D), CCl4+Rg1-20 mg/kg (E) and CCl4+Rg1-40 mg/kg (F). Scale bar, 100 μm. The inflammatory score (G) and balloon degeneration score (H) were evaluated in ten randomly selected fields from each slide at a magnification of ×200. All data were expressed as mean±SD of six animals. cP<0.01 vs control. fP<0.01 vs CCl4 alone.
Mentions: To determine the protective effects of Rg1 against CCl4-induced injury, we conducted histological examination of the extent of hepatic injury. According to microscopic examination, the administration of Rg1 alleviates severe hepatic lesions induced by alcohol and CCl4. Control rats had no pathological changes in either the lateral or median lobes of the liver (Figure 1A). Rats in the untreated fibrosis group had degenerative changes in the liver: centrilobular necrosis including ballooning of hepatocytes, deposition of lipid droplets in hepatocytes and infiltration of inflammatory cells, as well as collagen deposition17. In rats in the Rg1 10 mg/kg treated group, severe hepatocyte necrosis and ballooning degeneration were observed, as well as numerous inflammatory cells around the necrotic tissue (Figure 1D). Moderate hydropic degeneration of hepatocytes was shown in Rg1 20 mg/kg treated group. In the Rg1 40 mg/kg treated group, hepatocyte necrosis nearly disappeared (Figure 1F), showing a significant reduction in necrosis and hydropic degeneration. The inflammation score of each group was evaluated. As shown in Figure 1G, the inflammation score was 0.18±0.01 in the control group, while in the CCl4 group, the inflammation score was markedly increased (3.17±0.32, P<0.01). In contrast, compared with the untreated fibrosis group, treatment with Rg1 (10, 20, and 40 mg/kg) significantly reduced the increased inflammation scores (2.55±0.33, 2.05±0.19, and 1.62±0.50; P<0.05, P<0.01, and P<0.01, respectively). The balloon degeneration score (Figure 1H) was also significantly reduced by Rg1 (20 mg, 1.95±0.20 and 40 mg, 1.45±0.18; P<0.01, and P<0.01, respectively) compared with rats in the untreated fibrosis group (2.53±0.19).

Bottom Line: Rg1 significantly increased the activities of antioxidant enzymes (SOD, GSH-Px and CAT) and reduced MDA levels in liver tissues.Furthermore, Rg1 significantly increased the expression and nuclear translocation of Nrf2 that regulated the expression of many antioxidant enzymes.Knockdown of Nrf2 gene diminished these actions of Rg1 in CCl4-treated HSCs in vitro.

View Article: PubMed Central - PubMed

Affiliation: State Key of Laboratory Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.

ABSTRACT

Aim: To investigate the anti-fibrosis effects of ginsenoside Rg1 on alcohol- and CCl4-induced hepatic fibrosis in rats and to explore the mechanisms of the effects.

Methods: Rats were given 6% alcohol in water and injected with CCl4 (2 mL/kg, sc) twice a week for 8 weeks. Rg1 (10, 20 and 40 mg/kg per day, po) was administered in the last 2 weeks. Hepatic fibrosis was determined by measuring serum biochemical parameters, HE staining, Masson's trichromic staining, and hydroxyproline and α-SMA immunohistochemical staining of liver tissues. The activities of antioxidant enzymes, lipid peroxidation, and Nrf2 signaling pathway-related proteins (Nrf2, Ho-1 and Nqo1) in liver tissues were analyzed. Cultured hepatic stellate cells (HSCs) of rats were prepared for in vitro studies.

Results: In the alcohol- and CCl4-treated rats, Rg1 administration dose-dependently suppressed the marked increases of serum ALT, AST, LDH and ALP levels, inhibited liver inflammation and HSC activation and reduced liver fibrosis scores. Rg1 significantly increased the activities of antioxidant enzymes (SOD, GSH-Px and CAT) and reduced MDA levels in liver tissues. Furthermore, Rg1 significantly increased the expression and nuclear translocation of Nrf2 that regulated the expression of many antioxidant enzymes. Treatment of the cultured HSCs with Rg1 (1 μmol/L) induced Nrf2 translocation, and suppressed CCl4-induced cell proliferation, reversed CCl4- induced changes in MDA, GPX, PCIII and HA contents in the supernatant fluid and α-SMA expression in the cells. Knockdown of Nrf2 gene diminished these actions of Rg1 in CCl4-treated HSCs in vitro.

Conclusion: Rg1 exerts protective effects in a rat model of alcohol- and CCl4-induced hepatic fibrosis via promoting the nuclear translocation of Nrf2 and expression of antioxidant enzymes.

Show MeSH
Related in: MedlinePlus