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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 expression of Nrf2 pathway. (A) 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). (B) Rats were administered with saline and Rg1 (40 mg/kg) for two weeks (once a day). Western bloting analysis with the indicated antibodies. Histone H3 or β-Actin was used as an invariant control for equal loading. Representative blots were from three independent experiments. Data were expressed as mean±SD. Statistical evaluation was performed using t-test. Nucleus Nrf2 (A, B) and total Ho-1 and Nqo1 (A) were detected and analyzed. bP<0.05, cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.
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fig6: Effects of Rg1 on expression of Nrf2 pathway. (A) 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). (B) Rats were administered with saline and Rg1 (40 mg/kg) for two weeks (once a day). Western bloting analysis with the indicated antibodies. Histone H3 or β-Actin was used as an invariant control for equal loading. Representative blots were from three independent experiments. Data were expressed as mean±SD. Statistical evaluation was performed using t-test. Nucleus Nrf2 (A, B) and total Ho-1 and Nqo1 (A) were detected and analyzed. bP<0.05, cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.

Mentions: Nrf2 plays an important role in the activation of antioxidant enzymes by regulating their transcription26. As shown in Figure 6A, the nuclein Nrf2 protein of the untreated fibrosis rats showed a slight higher expression compared to the control group but no statistical significance. Compared with the control rats, the rats given with Rg1 (10, 20, and 40 mg) had markedly increased levels of Nrf2 (P<0.01, P<0.01, and P<0.01. Figure 6A). When compared to the untreated fibrosis rats, the Rg1 groups (10, 20, and 40 mg) had significantly increased levels of Nrf2 (P<0.05, P<0.01, and P<0.001. Figure 6A). The result implies that Rg1 promotes the nuclear translocation of the Nrf2 protein, which leads to recovery from alcohol-mediated acceleration of CCl4-induced liver fibrosis. The expression of Ho-1 and Nqo1 show the same tendency: Ho-1 was dramatically increased in three of the Rg1 groups (P<0.01, Figure 6A), as was Nqo1 (P<0.05, Figure 6A), in comparison to the expression in the control group.


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 expression of Nrf2 pathway. (A) 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). (B) Rats were administered with saline and Rg1 (40 mg/kg) for two weeks (once a day). Western bloting analysis with the indicated antibodies. Histone H3 or β-Actin was used as an invariant control for equal loading. Representative blots were from three independent experiments. Data were expressed as mean±SD. Statistical evaluation was performed using t-test. Nucleus Nrf2 (A, B) and total Ho-1 and Nqo1 (A) were detected and analyzed. bP<0.05, cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.
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fig6: Effects of Rg1 on expression of Nrf2 pathway. (A) 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). (B) Rats were administered with saline and Rg1 (40 mg/kg) for two weeks (once a day). Western bloting analysis with the indicated antibodies. Histone H3 or β-Actin was used as an invariant control for equal loading. Representative blots were from three independent experiments. Data were expressed as mean±SD. Statistical evaluation was performed using t-test. Nucleus Nrf2 (A, B) and total Ho-1 and Nqo1 (A) were detected and analyzed. bP<0.05, cP<0.01 vs control. eP<0.05, fP<0.01 vs CCl4 alone.
Mentions: Nrf2 plays an important role in the activation of antioxidant enzymes by regulating their transcription26. As shown in Figure 6A, the nuclein Nrf2 protein of the untreated fibrosis rats showed a slight higher expression compared to the control group but no statistical significance. Compared with the control rats, the rats given with Rg1 (10, 20, and 40 mg) had markedly increased levels of Nrf2 (P<0.01, P<0.01, and P<0.01. Figure 6A). When compared to the untreated fibrosis rats, the Rg1 groups (10, 20, and 40 mg) had significantly increased levels of Nrf2 (P<0.05, P<0.01, and P<0.001. Figure 6A). The result implies that Rg1 promotes the nuclear translocation of the Nrf2 protein, which leads to recovery from alcohol-mediated acceleration of CCl4-induced liver fibrosis. The expression of Ho-1 and Nqo1 show the same tendency: Ho-1 was dramatically increased in three of the Rg1 groups (P<0.01, Figure 6A), as was Nqo1 (P<0.05, Figure 6A), in comparison to the expression in the control group.

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