Limits...
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.

Show MeSH

Related in: MedlinePlus

Effects of Rg1 on CCl4-induced expression of hepatic α-SMA. Representative photomicrographs of liver histology 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). Original magnification: ×100. Scale bar, 100 μm. (G) Morphometrical analysis was performed for evaluating percentages of α-SMA-positive area in 12 random fields per section of six animals. (H) Western bloting analysis of α-SMA in liver tissue. Representative blots were from three independent experiments. The data were expressed as means±SD. cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4125711&req=5

fig3: Effects of Rg1 on CCl4-induced expression of hepatic α-SMA. Representative photomicrographs of liver histology 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). Original magnification: ×100. Scale bar, 100 μm. (G) Morphometrical analysis was performed for evaluating percentages of α-SMA-positive area in 12 random fields per section of six animals. (H) Western bloting analysis of α-SMA in liver tissue. Representative blots were from three independent experiments. The data were expressed as means±SD. cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.

Mentions: The protective effect of Rg1 in hepatic fibrosis is associated with the inhibition of HSC activation, which was determined by the inhibition of α-SMA+ myofibroblast transition. Almost no expression of α-SMA was observed in the control rat livers (Figure 3A). Many α-SMA positive cells appear in untreated fibrotic liver and the positive areas are connected, dividing the liver into many annular lobules (Figure 3B). Rg1 reduced the α-SMA positive area in a dose-dependent manner (Figure 3D–3F). Much of the α-SMA expression remained evident in the Rg1-10 mg group, spreading from the portal area and linking positive areas together, occasionally forming false lobules (Figure 3D). Most of the α-SMA positive areas in the Rg1 20 mg group concentrated around the portal area, with a rare false flocculus structure. In the Rg1-40 mg group, almost all of the α-SMA-positive areas concentrated around the portal area with a shorter distance and a smaller area, and no false flocculus structures were observed. α-SMA positive area analysis showed that rats administered with 20 and 40 mg/kg Rg1 significantly block the α-SMA+ cell accumulation (6.33%±2.08% and 4.21%±1.97%; P<0.05, P<0.01) compared with the control group (9.26%±2.28%, P<0.01 vs control group. Figure 3G).


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 CCl4-induced expression of hepatic α-SMA. Representative photomicrographs of liver histology 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). Original magnification: ×100. Scale bar, 100 μm. (G) Morphometrical analysis was performed for evaluating percentages of α-SMA-positive area in 12 random fields per section of six animals. (H) Western bloting analysis of α-SMA in liver tissue. Representative blots were from three independent experiments. The data were expressed as means±SD. cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4125711&req=5

fig3: Effects of Rg1 on CCl4-induced expression of hepatic α-SMA. Representative photomicrographs of liver histology 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). Original magnification: ×100. Scale bar, 100 μm. (G) Morphometrical analysis was performed for evaluating percentages of α-SMA-positive area in 12 random fields per section of six animals. (H) Western bloting analysis of α-SMA in liver tissue. Representative blots were from three independent experiments. The data were expressed as means±SD. cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.
Mentions: The protective effect of Rg1 in hepatic fibrosis is associated with the inhibition of HSC activation, which was determined by the inhibition of α-SMA+ myofibroblast transition. Almost no expression of α-SMA was observed in the control rat livers (Figure 3A). Many α-SMA positive cells appear in untreated fibrotic liver and the positive areas are connected, dividing the liver into many annular lobules (Figure 3B). Rg1 reduced the α-SMA positive area in a dose-dependent manner (Figure 3D–3F). Much of the α-SMA expression remained evident in the Rg1-10 mg group, spreading from the portal area and linking positive areas together, occasionally forming false lobules (Figure 3D). Most of the α-SMA positive areas in the Rg1 20 mg group concentrated around the portal area, with a rare false flocculus structure. In the Rg1-40 mg group, almost all of the α-SMA-positive areas concentrated around the portal area with a shorter distance and a smaller area, and no false flocculus structures were observed. α-SMA positive area analysis showed that rats administered with 20 and 40 mg/kg Rg1 significantly block the α-SMA+ cell accumulation (6.33%±2.08% and 4.21%±1.97%; P<0.05, P<0.01) compared with the control group (9.26%±2.28%, P<0.01 vs control group. Figure 3G).

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