Isorhamnetin-3-O-galactoside Protects against CCl4-Induced Hepatic Injury in Mice

This study was performed to examine the hepatoprotective effect of isorhamnetin-3-O-galactoside, a flavonoid glycoside isolated from Artemisia capillaris Thunberg (Compositae), against carbon tetrachloride (CCl₄)-induced hepatic injury. Mice were treated intraperitoneally with vehicle or isorhamnetin-3-O-galactoside (50, 100, and 200 mg/kg) 30 min before and 2 h after CCl₄ (20 μl/kg) injection. Serum aminotransferase activities and hepatic level of malondialdehyde were significantly higher after CCl₄ treatment, and these increases were attenuated by isorhamnetin-3-O-galactoside. CCl₄ markedly increased serum tumor necrosis factor-α level, which was reduced by isorhamnetin-3-O-galactoside. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase- 2 (COX-2), and heme oxygenase-1 (HO-1) protein and their mRNA expression levels were significantly increased after CCl₄ injection. The levels of HO-1 protein and mRNA expression levels were augmented by isorhamnetin-3-O-galactoside, while isorhamnetin- 3-O-galactoside attenuated the increases in iNOS and COX-2 protein and mRNA expression levels. CCl₄ increased the level of phosphorylated c-Jun N-terminal kinase, extracellular signal-regulated kinase and p38, and isorhamnetin-3-O-galactoside reduced these increases. The nuclear translocation of nuclear factor kappa B (NF-κB), activating protein-1, and nuclear factor erythroid 2-related factor 2 (Nrf2) were signifi cantly increased after CCl₄ administration. Isorhamnetin-3-O-galactoside attenuated the increases of NF_-κB and c-Jun nuclear translocation, while it augmented the nuclear level of Nrf2. These results suggest that isorhamnetin-3-O-galactoside ameliorates CCl₄-induced hepatic damage by enhancing the anti-oxidative defense system and reducing the inflammatory signaling pathways.     

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

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 CCl_4- 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.     

Protective effects of Dunaliella salina – A carotenoids-rich alga,against carbon tetrachloride-induced hepatotoxicity in mice

The protective effects of Dunaliella salina (D. salina) on liver damage were evaluated by carbon tetrachloride (CCl₄)-induced hepatotoxicity in mice. Male ICR mice were orally treated with D. salina or silymairn daily with administration of CCl₄ twice a week for 8 weeks. CCl₄ induced liver damage and significantly (p < 0.05) increased the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) in serum and decreased the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), and GSH content in liver whereas increased hepatic malondialdehyde (MDA) content as compared with control group. Treatment with D. salina or silymarin could significantly (p < 0.05) decrease the ALT, AST, and ALP levels in serum and increase the activities of SOD, catalase, GSH-Px, glutathione reductase, and GSH content and decrease the MDA content in liver when compared with CCl₄-treated group. Liver histopathology also showed that D. salina reduced the incidence of liver lesions induced by CCl₄. The results suggest that D. salina exhibits potent hepatoprotective effects on CCl₄-induced liver damages in mice, and that the hepatoprotective effects of D. salina may be due to both the increase of antioxidant enzymes activities and inhibition of lipid peroxidation.     

Effect of flavonoids from Prosthechea michuacana on carbon tetrachloride induced acute hepatotoxicity in mice

Context: Prosthechea michuacana W.E. Higgins (LaLlave & Lex) (Orchidaceae) is an orchid that has been used in traditional medicine for the treatment of inflammation, diabetes, wound, and liver disorders. Therefore, we thought it would be worthwhile to study the effect of this orchid on liver damage using mice as model.

Objective: The present study investigates the effect of flavonoids isolated from methanol extract of P. michuacana on carbon tetrachloride (CCl₄)-induced liver damage in mice.

Materials and methods: The methanol extract was purified by repeated column chromatography, resulting in the identification of five metabolites whose hepatoprotective effects were evaluated by measuring aspartate transaminase, alanine transaminase, alkaline phosphatase, glutamate, total bilirubin level, lactate dehydrogenase, total serum protein, and lipid peroxidation (thiobarbituric acid reactive substances assay) in CCl₄-induced hepatic injury in mice.

Results: From the bulbs of P. michuacana, four known flavonoids were isolated (scutellarein 6-methyl ether, dihydroquercetin, apigenin 7-O-glucoside, and apigenin-7-neohesperidoside), together with the new flavonol glycoside apigenin-6-O-β-d-glucopyranosil-3-O-α-l-rhamnopyranoside. Their structures were characterized by 1D and 2D nuclear magnetic resonance experiments. Treatment with flavonoids significantly prevented the biochemical measurable changes induced by CCl₄ in the liver. Compounds 1, 4, and 5 were found to exhibit good hepatoprotective effect. These effects were comparable to that of the standard drug silymarin, a well-known hepatoprotective agent.

Discussion: These results demonstrate that flavonoids contained in the bulbs of P. michuacana contribute to the hepatoprotective activity attributed to the plant.     

Enhanced liver injury in acatalasemic mice following exposure to carbon tetrachloride

The hypothtical involvement of hydrogen peroxide (H₂O₂) in carbon tetrachloride (CCl₄)-induced acute liver injury and the potential preventive effect of catalase on hepatotoxicity have been studied in acatalasemic (C3H/AnLC_s ^bC₂ ^b) mice and compared with normal (C3H/AnLC_s ^aC_s ^a) mice. A single intraperitoneal injection of CCl₄ (20% in olive oil/g body weight) caused increases in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in both mouse groups, but the extents of increases did not show significant differences between the two mouse groups until 12 h. The variation in increases of serum AST and ALT levels in acatalasemic and normal mice turned to be distinctly different from 12 h. At 18 h (peak point for ALT) and 24 h (peak point for AST), the serum enzyme levels in acatalasemic mice were nearly two-fold higher than those in normal ones, the difference being statistically significant (p <0.01). The liver malondialdehyde (MDA) level in acatalasemic mice was also higher than that in normals at 18 h (p <0.05). The extent of the centrilobular necrosis was histologically more severe in acatalasemic mice. The catalase activity in livers of acatalasemic mice was one-third to one-fifth those of normal mice (p <0.05) before and after treatment. The decreased catalase activity in acatalasemic mice might increase tissue or cellular levels of H₂O₂ during the later phase of the acute liver injury. From these findings, we conclude that H₂O₂ breakdown in liver would account for the difference in the later stages of the acute liver damage between the two groups of mice, and catalase is important in inhibiting hepatotoxicity of CCl₄ in the later stage.     

Protective effects of silica hydride against carbon tetrachloride-induced hepatotoxicity in mice

The protective effects of MegaHydrate™ silica hydride against liver damage were evaluated by its attenuation of carbon tetrachloride (CCl₄)-induced hepatotoxicity in mice. Male ICR mice were orally treated with silica hydride (104, 208 and 520 mg/kg) or silymarin (200 mg/kg) daily, with administration of CCl₄ (1 mL/kg, 20% CCl4 in olive oil) twice a week for eight weeks. The results showed that oral administration of silica hydride significantly reduced the elevated serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), triglyceride (TG), and cholesterol and the level of malondialdehyde (MDA) in the liver that were induced by CCl₄ in mice. Moreover, the silica-hydride treatment was also found to significantly increase the activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px), as well as increase the GSH content, in the liver. Liver histopathology also showed that silica hydride reduced the incidence of liver lesions induced by CCl₄. The results suggest that silica hydride exhibits potent hepatoprotective effects on CCl₄-induced liver damage in mice, likely due to both the increase of antioxidant-defense system activity and the inhibition of lipid peroxidation.     

Comparative evaluation of the protective potentials of human paraoxonase 1 and 3 against CCl4-induced liver injury

We previously reported that electroporation mediated hPON1 or hPON3 gene delivery could protect against CCl₄-induced liver injury. However, substantial evidence supported that the in vivo physiological functions of hPON1 and hPON3 were distinct. To compare the protective efficacies of hPON1 and hPON3 against liver injury, recombinant adenovirus AdPON1 and AdPON3, which were capable of expressing hPON1 and hPON3 respectively, were intravenously injected into mice before they were given CCl₄. Adenovirus mediated expression of hPON1 and hPON3 were demonstrated by elevated serum esterase activity, hepatic lactonase activity, and hPON1/hPON3 mRNA expression in liver. Serum transaminase assay, histological observation and TUNEL analysis revealed that the extent of liver injury and hepatocyte apoptosis in AdPON1 or AdPON3 treated mice was significantly ameliorated in comparison with control. Meanwhile, overexpression of hPON1 and hPON3 reduced the hepatic oxidative stress and strengthen the total antioxidant capabilities in liver through affecting the hepatic malondialdehyde (MDA), glutathione (GSH) and total antioxidant capability (T-AOC) levels, regardless of the exposure to CCl₄ or corn oil. Administration of AdPON1 or AdPON3 also suppressed inflammatory response by decreasing TNF-α and IL-1β levels in CCl₄ mice. In this study, hPON1 exhibited a slightly higher efficacy than hPON3 in alleviating liver injury, but the difference between them were not significant.     

Hepatoprotective effect of electrolyzed reduced water against carbon tetrachloride-induced liver damage in mice

The study investigated the protective effect of electrolyzed reduced water (ERW) against carbon tetrachloride (CCl₄)-induced liver damage. Male ICR mice were randomly divided into control, CCl₄, CCl₄ + silymarin, and CCl₄ + ERW groups. CCl₄-induced liver lesions include leukocytes infiltration, hepatocyte necrosis, ballooning degeneration, mitosis, calcification, fibrosis and an increase of serum alanine aminotransferase (ALT), and aminotransferase (AST) activity. In addition, CCl₄ also significantly decreased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). By contrast, ERW or silymarin supplement significantly ameliorated the CCl₄-induced liver lesions, lowered the serum levels of hepatic enzyme markers (ALT and AST) and increased the activities of SOD, catalase, and GSH-Px in liver. Therefore, the results of this study show that ERW can be proposed to protect the liver against CCl₄-induced oxidative damage in mice, and the hepatoprotective effect might be correlated with its antioxidant and free radical scavenging effect.     

Flavonoid constituents of Dobera glabra leaves: amelioration impact against CCl4-induced changes in the genetic materials in male rats

Context: Dobera glabra (Forssk.) Poir (Salvadoraceae) is a highly valued tree with diverse importance as special mineral sourced feed and a folkloric tool for forecasting droughts. However, there are no reports on its phytochemical and biological investigations.

Objective: Phytochemical investigation of D. glabra leaves and its protective potential against CCl₄ inducing changes in the genetic materials.

Materials and methods: D. glabra extract, DGE (70% MeOH/H₂O), was applied to polyamide column chromatography, eluting with MeOH/H₂O of decreasing polarities, followed by preparative chromatographic tools, yielded seven compounds. Three DGE doses (50, 100 and 200?mg/kg bw/d) were administrated for 8 weeks intragastrically to male albino rats prior treated with CCl₄ (0.5?mL/kg/bw). The reactive oxygen species (ROS) levels, expression changes of glutamate transporters (GLAST, GLT-1 and SNAT3) mRNA, DNA fragmentation and glutathione peroxidase (GPx) activity were investigated in the liver tissues of these rats.

Results: Isorhamnetin-3-O-β-glucopyranoside-7-O-α-rhamnopyranoside, isorhamnetin-3-O-α-rhamnopyranoside-7-O-β-glucopyranoside, kaempferol-3,7-di-O-α-rhamnopyranoside, isorhamnetin-3-O-β-glucopyranoside, kaempferol-3-O-β-glucopyranoside, isorhamnetin and kaempferol were identified. DGE (200?mg/kg bw)?+?CCl₄ exhibited the most significant reduction in ROS levels and DNA fragmentation with 251.3% and141% compared to 523.1% and 273.2% for CCl₄, respectively. Additionally, it increased significantly the mRNA expression of GLAST, GLT-1 and SNAT3 to 2.16-, 1.72- and 2.09-fold, respectively. Also, GPx activity was increased to 4.8?U/mg protein/min compared to CCl₄ (1.8?U/mg protein/min).

Discussion and conclusion: Flavonoid constituents, antioxidant effect and genotoxic protection activity of D. glabra were first reported. DGE may be valuable in the treatment and hindrance of hepatic oxidative stress and genotoxicity.     

Protection of the flavonoid fraction from Rosa laevigata Michx fruit against carbon tetrachloride-induced acute liver injury in mice

Protective effect of the total flavonoids (TFs) from Rosa laevigata Michx fruit against carbon tetrachloride (CCl₄)-induced hepatotoxicity in mice was investigated. Pretreatment with TFs significantly decreased CCl₄-induced elevation of serum aspartate transaminase (AST) and alanine transaminase (ALT) activities as well as the relative liver weight. Histopathological observation also revealed that TFs reduced the incidence of liver lesions and improved hepatocyte abnormality. Moreover, oral administration of TFs significantly enhanced antioxidant enzyme activities (superoxide dismutase, catalase and glutathione peroxidase), increased the content of glutathione and decreased the content of malondialdehyde. Further research indicated that TFs prevented the DNA fragmentation and mitochondrial ultrastructural alterations caused by CCl₄ based on TUNEL and transmission electron microscopy (TEM) assays. Moreover, pretreatment with TFs down-regulated the protein expressions of CYP2E1, iNOS, NF-κB, Bak and Caspase-3. Quantitative Real-time PCR assay suggested that TFs markedly decreased the levels of TNF-α, Fas/FasL and Bax gene expressions, and increased the level of Bcl-2. This is the first time to report the significant hepatoprotective effect of TFs from R. laevigata Michx fruit against CCl₄-induced liver injury in mice and the action should be through reducing oxidative stress and suppressing inflammation and apoptosis.     

Protective effect of wedelolactone against CCl4-induced acute liver injury in mice

Eclipta, a traditional Chinese medicine, has been used to treat liver disease for centuries. However, the chemical basis and biological mechanisms of Eclipta remain elusive. The current study aims to investigate the hepatoprotective effect of wedelolactone (WEL), a major coumarin in Eclipta, using C57BL/6 mice with carbon tetrachloride CCl₄-induced acute liver injury (ALI). Our data showed that WEL markedly decreased the CCl₄-induced elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, and improved hepatic histopathology changes. WEL also significantly decreased the content of MDA in liver tissues, meanwhile increased the activities of antioxidant enzymes SOD and GSH-Px. In addition, WEL reduced the protein expression of TNF-α, IL-1β and IL-6, as well as mRNA expression. Western blot results revealed that WEL repressed phosphorylation of extracellular signal-regulated kinase (ERK) and translocation of NF-κB p65 from cytoplasm to nucleus and enhanced the phosphorylation of c-Jun. N-terminal kinase (JNK). Moreover, results showed that WEL significantly inhibited CCl₄-induced hepatocytes apoptosis, markedly suppressed the down-regulation of Bax and active Caspase-3 expression and accelerated the expression of Bcl-2. Overall, the findings indicate that WEL exhibits a protective effect against CCl₄-induced ALI in mice by enhancing the antioxidative defense system, suppressing the inflammatory response and cell apoptosis of liver.     

Protective Effect of a Mixture of Aloe vera and Silybum marianum Against Carbon Tetrachloride–Induced Acute Hepatotoxicity and Liver Fibrosis

The hepatoprotective effects of ACTIValoe^®N-931 complex, a mixture of Aloe vera and Silybum marianum, against acute and chronic carbon tetrachloride (CCl₄)-induced liver injuries were investigated. Acute hepatotoxicity was induced by intraperitoneal injection of CCl₄ (50 μl/kg), and ACTIValoe^®N-931 complex at 85, 170, and 340 mg/kg was administered orally 48, 24, and 2 h before and 6 h after injection of CCl₄. Hepatotoxicity was assessed 24 h after CCl₄ treatment. Liver fibrosis was induced by intraperitoneal injection of CCl₄ for 8 weeks (0.5 ml/kg, twice per week), and mice were treated with ACTIValoe^®N-931 complex at 85, 170, or 340 mg/kg once a day (p.o.). In both acute hepatotoxicity and liver fibrosis, serum amino-transferase levels and lipid peroxidation were increased and the hepatic glutathione content was decreased. These changes were prevented by ACTIValoe^®N-931 complex. The ACTIValoe^®N-931 complex attenuated the increase in tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), mRNA expressions in acute hepatotoxicity. In antifibrotic experiments, tissue inhibitor of metalloprotease-1 (TIMP-1) mRNA expression was attenuated by treatment with ACTIValoe^®N-931 complex. The ACTIValoe^®N-931 complex decreased the hepatic hydroxyproline content and the transforming growth factor-beta1 levels. Our results suggest that the ACTIValoe^®N-931 complex has hepatoprotective effects in both acute and chronic liver injuries induced by CCl₄.     

Ferulic acid protects against carbon tetrachloride-induced liver injury in mice

Ferulic acid (FA), isolated from the root of Scrophularia buergeriana, is a phenolic compound possessing antioxidant, anticancer, and antiinflammatory activities. Here, we have investigated the hepatoprotective effect of FA against carbon tetrachloride (CCl₄)-induced acute liver injury. Mice were treated intraperitoneally with vehicle or FA (20, 40, and 80 mg/kg) 1 h before and 2 h after CCl₄ (20 μl/kg) injection. The serum activities of aminotransferases and the hepatic level of malondialdehyde were significantly higher after CCl₄ treatment, while the concentration of reduced glutathione was lower. These changes were attenuated by FA. The serum level and mRNA expression of tumor necrosis factor-α significantly increased after CCl₄ treatment, and FA attenuated these increases. The levels of inducible nitric oxide synthase and cyclooxygenase-2 protein and mRNA expression after CCl₄ treatment were significantly higher and FA reduced these increases. CCl₄-treated mice showed increased nuclear translocation of nuclear factor-κB (NF-κB), and decreased levels of inhibitors of NF-κB in cytosol. Also, CCl₄ significantly increased the level of phosphorylated JNK and p38 mitogen-activated protein (MAP) kinase, and nuclear translocation of activated c-Jun. FA significantly attenuated these changes. We also found that acute CCl₄ challenge induced TLR4, TLR2, and TLR9 protein and mRNA expression, and FA significantly inhibited TLR4 expression. These results suggest that FA protects from CCl₄-induced acute liver injury through reduction of oxidative damage and inflammatory signaling pathways.     

Hepatoprotective effect of the ethanol extract of Polygonum orientale on carbon tetrachloride-induced acute liver injury in mice

Polygonum orientale L. (Polygonaceae) fruits have various medicinal uses, but their hepatoprotective effects have not yet been studied. This study investigated the hepatoprotective activity of the ethanolic extract of P. orientale (POE) fruits against carbon tetrachloride (CCl₄)-induced acute liver injury (ALI). Mice were pretreated with POE (0.1, 0.5, and 1.0 g/kg) or silymarin (0.2 g/kg) for 5 consecutive days and administered a dose of 0.175% CCl₄ (ip) on the 5th day to induce ALI. Blood and liver samples were collected to measure antioxidative activity and cytokines. The bioactive components of POE were identified through high-performance liquid chromatography (HPLC). Acute toxicity testing indicated that the LD₅₀ of POE exceeded 10 g/kg in mice. Mice pretreated with POE (0.5, 1.0 g/kg) experienced a significant reduction in their serum aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), and alkaline phosphatase (ALP) levels and reduction in the extent of liver lesions. POE reduced the malondialdehyde (MDA), nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) levels, and increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GRd) in liver. HPLC revealed peaks at 11.28, 19.55, and 39.40 min for protocatechuic acid, taxifolin, and quercetin, respectively. In summary, the hepatoprotective effect of POE against CCl₄-induced ALI was seemingly associated with its antioxidant and anti-proinflammatory activities.     

Hepatoprotective activity of Leptadenia reticulata stems against carbon tetrachloride-induced hepatotoxicity in rats

Objective:

To evaluate the hepatoprotective activity of ethanolic and aqueous extract of stems of Leptadenia reticulata (Retz.) Wight. and Arn. in carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats.

Materials and Methods:

The toxicant CCl₄ was used to induce hepatotoxicity at a dose of 1.25 ml/kg as 1 : 1 mixture with olive oil. Ethanolic and aqueous extracts of L. reticulata stems were administered in the doses of 250 and 500 mg/kg/day orally for 7 days. Silymarin (50 mg/kg) was used as standard drug. The hepatoprotective effect of these extracts was evaluated by the assessment of biochemical parameters such as serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, total bilirubin, serum protein, and histopathological studies of the liver.

Results:

Treatment of animals with ethanolic and aqueous extracts significantly reduced the liver damage and the symptoms of liver injury by restoration of architecture of liver as indicated by lower levels of serum bilirubin and protein as compared with the normal and silymarin-treated groups. Histology of the liver sections confirmed that the extracts prevented hepatic damage induced by CCl₄ showing the presence of normal hepatic cords, absence of necrosis, and fatty infiltration.

Conclusion:

The ethanolic and aqueous extracts of stems of L. reticulata showed significant hepatoprotective activity. The ethanolic extract is more potent in hepatoprotection in CCl₄-indiced liver injury model as compared with aqueous extract.     

Intermittent dosing of G-CSF to ameliorate carbon tetrachloride-induced liver fibrosis in mice

On the basis of the recent report that granulocyte colony-stimulating factor (G-CSF) administration after rats’ partial orthotopic liver transplantation greatly improved survival rate and liver regeneration of partial graft, we here evaluated the effect of intermittent administration of G-CSF on fibrosis formation induced by carbon tetrachloride (CCl₄). Bone marrow chimeric female C57BL/6 mice were treated with G-CSF at days 1, 7, 14, 21, and 28 after CCl₄ challenge. At day 35 after CCl₄ administration, we found that G-CSF treatment significantly reduced CCl₄-induced liver damage and collagen deposition. In addition, levels of hepatic hydroxyproline and serum fibrosis markers in mice receiving G-CSF administration after CCl₄ challenge were significantly lower compared to those of control mice. Histological examination suggested that hepatic damage recovery was much better in these G-CSF-treated mice. Immunofluorescence and fluorescence in situ hybridization (FISH) analysis revealed that donor cells engrafted into host liver, had epithelium-like morphology and expressed albumin, although at low frequency. These results suggest that intermittent G-CSF treatment might initiate endogenous hepatic tissue regeneration in response to CCl₄ injury and ameliorate its fibrogenic effects.     

Protective effect of the Aralia continentalis root extract against carbon tetrachloride-induced hepatotoxicity in mice

The root of Aralia continentalis Kitagawa has been used in traditional Korean medicine to relieve pain and to treat inflammation. The purpose of this study was to investigate the protective effects of the extract of A. continentalis roots (AC) against hepatotoxicity induced by carbon tetrachloride (CCl₄) and the mechanism of its hepatoprotective effect. In mice, pretreatment with AC prior to the administration of CCl₄ significantly prevented the increased serum enzymatic activity of ALT and AST as well as the formation of hepatic malondialdehyde. Histopathological evaluation of the livers also revealed that AC reduced the incidence of liver lesions induced by CCl₄. In addition, pretreatment with AC significantly prevented both the depletion of reduced glutathione (GSH) content and the decrease in glutathione-S-transferase (GST) activity in the liver of CCl₄-intoxicated mice. Hepatic GSH levels and GST activity were increased by treatment with AC alone. Heme oxygenase-1 (HO-1) is known to be induced by oxidative stress and to confer protection against oxidative tissue injuries. Interestingly, AC markedly upregulated hepatic HO-1 expression in CCl₄-treated mice, which might provide anti-oxidative activity in the liver. These results indicate that AC plays a critical protective role in CCl₄-induced acute liver injury by promoting anti-oxidative protein expression.     

Studies on the role of protein synthesis in cell injury by toxic agents: I. Effect of cycloheximide administration on several factors modulating carbon tetrachloride-induced liver necrosis

Cycloheximide pretreatment (1 mg/kg, ip) slightly attenuated the hepatic necrosis 24 hr after CCl₄ administration and this attenuation was more obvious at 72 hr. A dose of cycloheximide, 2 mg/kg, evoked a marked protective effect even at 24 hr. Cycloheximide administration (1 mg/kg) significantly reduced the body temperature in CCl₄-treated rats but did not change the CCl₄ concentrations in the liver. Prior treatment of the rats with cycloheximide decreased the amount of binding of ¹⁴CCl₄ to liver microsomal lipids and reduced CCl₄-induced lipid peroxidation at 1 hr but not at 6 hr after administration of the hepatotoxin. Cycloheximide did not alter the pentobarbital sleeping time of the rats nor did it interact with microsomes to give spectral changes. Cycloheximide did not alter microsomal cytochrome P-450 reductase activity. Administration of cycloheximide prior to CCl₄ did not prevent the CCl₄-induced decrease in cytochrome P-450 or glucose 6-phosphatase activity caused by the hepatotoxin. However it did prevent the CCl₄-induced polysome breakdown and it did attenuate the severity of the lesions caused by CCl₄ at the ultrastructural level.     

Protective effects of the total saponins from Dioscorea nipponica Makino against carbon tetrachloride-induced liver injury in mice through suppression of apoptosis and inflammation

The present study was to investigate the effects and possible mechanisms of the total saponins from Dioscorea nipponica Makino (TSDN) against CCl₄-induced hepato-toxicity in mice. The mice were orally administrated with TSDN for seven days and then given CCl₄ (0.3%, 10 ml/kg i.p.). The results showed that TSDN significantly attenuated the activities of ALT and AST, consistent with hematoxylin–eosin staining. The ALP levels and relative liver weight were significantly decreased by TSDN compared with model group. Moreover, TSDN dramatically decreased MDA, iNOS and NO levels, while the levels of GSH, GSH-Px and SOD were increased. Further investigations showed that TSDN inhibited CCl₄-induced metabolic activation and CYP2E1 expression, down-regulated the levels of MAPKs phosphorylation, NF-κB, HMGB1, COX-2 as well as effectively suppressed the expressions of Caspase-3, Caspase-9, PARP and Bak. Quantitative real-time PCR assay demonstrated that TSDN obviously decreased the gene expressions of TNF-a, IL-1β, IL-6, IL-10, Fas, FasL, Bax as well as modulated Bcl-2 mRNA level. This is the first time to report the protective actions of the TSDN against CCl₄-induced liver damage in mice through suppression of inflammation and apoptosis. This natural product should be developed as a new drug for treatment of liver injury in future.