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BACKGROUND Acute chemical liver injury needs to be further explored. The present study aimed to compare the effects of intraperitoneal injection with carbon tetrachloride on acute liver toxicity after 24 h in male and female Kunming mice. MATERIAL AND METHODS In this study, female and male mice were simultaneously divided into 3 different groups. Each group was treated differently, and after 24 h, blood samples were collected to check for changes in the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which were used to assess liver toxicity. Liver samples were used for hematoxylin-eosin staining, and periodic acid Schiff reagent staining was performed to detect the pathological changes of each group. The expression level of biomarker molecules in liver cells was also systematically analyzed. RESULTS Our results showed that, compared with male mice, female mice showed more serious damage: reduced glycogen and higher degree of necrosis, and the levels of heatshock protein 27 (HSP27), heat-shock protein 70 (HSP70), proliferating cell nuclear antigen (PCNA) and B cell lymphoma/lewkmia-2 (Bcl-2) were significantly lower than in the male group (P<0.05 or P<0.01), while the results of Bcl-2-associated X protein (Bax), cysteinyl aspartate specific proteinase 3 (Caspase3), and cytochrome P450 2E1 (CYP2E1) were the opposite (P<0.05 or P<0.01). CONCLUSIONS The findings from this study showed that, compared with male mice, at 24 h after CCl₄ toxicity, female mice showed more severe changes of hepatocyte necrosis and PAS-positivity, with significantly reduced expression of HSP27, HSP70, PCNA, and Bcl-2, and significantly increased expression of Bax, caspase-3, and CYP2E1.

The lack of Lipocalin (LCN2) provokes overwhelming endoplasmic reticulum (ER) stress responses in vitro and in acute toxic liver injury models, resulting in hepatocyte apoptosis. LCN2 is an acute phase protein produced in hepatocytes in response to acute liver injuries. In line with these findings we investigated ER stress responses of Lcn2 mice in chronic ER stress using a long-term repetitive carbon tetrachloride (CCl -/- mice in chronic ER stress using a long-term repetitive carbon tetrachloride (CCl 4 ) injection model. We found chronic CCl 4 application to enhance ER stress and unfolded protein responses (UPR), including phosphorylation of eukaryotic initiation factor 2α (eIF2α), increased expression of binding immunoglobulin protein (BiP) and glucose-regulated protein 94 (GRP94). IRE1α/TRAF2/JNK signaling enhanced mitochondrial apoptotic pathways, and showed slightly higher in Lcn2 -/- mice compared to the wild type counterparts, leading to increased hepatocyte apoptosis well evidenced by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Hepatocyte injuries were confirmed by significant high serum alanine transaminase (ALT) levels in CCl 4 -treated Lcn2 -/- mice. Lcn2 -/- mice furthermore developed mild hepatic steatosis, supporting our finding that ER stress promotes lipogenesis. In a previous report we demonstrated that the pharmacological agent tunicamycin (TM) induced ER stress through altered protein glycosylation and induced high amounts of C/EBP-homologous protein (CHOP), resulting in hepatocyte apoptosis. We compared TM-induced ER stress in wild type, Lcn2 -/- , and Chop null ( Chop -/- ) primary hepatocytes and found Chop -/- hepatocytes to attenuate ER stress responses and resist ER stress-induced hepatocyte apoptosis through canonical eIF2α/GADD34 signaling, inhibiting protein synthesis. Unexpectedly, in later stages of TM incubation, Chop -/- hepatocytes resumed activation of IRE1α/JNK/c-Jun and p38/ATF2 signaling, leading to late hepatocyte apoptosis. This interesting observation indicates Chop -/- mice to be unable to absolutely prevent all types of liver injury, while LCN2 protects the hepatocytes by maintaining homeostasis under ER stress conditions.

Carbon tetrachloride (CCl4) is widely used to induce hepatic fibrosis. Therapeutic agents alleviate hepatic fibrosis by inhibiting signal transducer and activator of transcription 3 (STAT3) activation. To understand the direct effects of CCl4 on STAT3 expression in the liver, the present study incubated cultured hepatocytes expressing connective tissue growth factor (CTGF) with CCl4. Rats exposed to CCl4 for 8 weeks exhibited hepatic fibrosis, which was confirmed through the assessment of plasma biomarkers. Isolated liver samples were used to determine the protein levels of CTGF and STAT3 using western blotting. In addition, STAT3 expression was silenced in α mouse liver 12 (AML‑12) cells using small interfering RNA transfection. In addition, a pharmacological inhibitor, stattic, was used to inhibit STAT3 expression. The incubation of AML‑12 cells with CCl4 induced a dose‑dependent increase in CTGF expression and STAT3 activation. Notably, silymarin, an extract from milk thistle, inhibited these changes in AML‑12 cells and the antioxidant tiron produced similar effects. Silencing of STAT3 reduced the CTGF expression promoted by CCl4 in the hepatocytes. Additionally, similar to tiron, stattic inhibited CTGF expression induced by CCl4. In conclusion, CCl4 may activate STAT3 through oxidative stress to promote CTGF expression, which is one of the main factors contributing to the risk of hepatic fibrosis.

The underlined effects of diallyl sulfide (DAS) against CCL 4 -induced oxidative, inflammatory, and apoptotic acute hepatic damage were assessed. Administration of DAS (50, 100, and 200 mg/kg) along with CCL 4 effectively mitigated serum aspartate aminotransferase, alanine aminotransferase activities, MDA, TNF-α, IL-1β, and MCP-1 levels, as well as significantly restored HO-1, GSH levels and SOD activity in liver tissues compared with those in rats treated with CCL 4 . Moreover, DAS inhibited CCL 4 -induced increase of liver NF-κB (p65), Bax, p38 MAPK, and JNK protein expression. In addition, DAS accelerated protein expression of Nrf2 and Bcl-2. The hepatoprotective properties of DAS were further confirmed by the reduced severity of hepatic damage as demonstrated by histopathological findings. In conclusion, DAS achieved its protective potential against CCL4-induced hepatotoxicity through antiapoptotic activity, as well as the synchronized modulation of NF-κB and Nrf2 for the favor of antioxidant/anti-inflammatory effects via suppression of the upstream stress-activated MAPKs pathways., (© 2019 Wiley Periodicals, Inc.)

The purpose. To study the effect of partial hepatectomy (PH) on the main ways of ammonia detoxication in the liver (synthesis of urea and glutamine) in chronic tetrachlorcarbon (CCl4) hepatitis. Methods. The experiments were performed on 165 white outbred rats (females) weighing 180-220 g Chronic CCl4-hepatitis was reproduced by subcutaneous injection of 50% CCl4 solution in olive oil (0.1 ml/100g of body weight,65 days, through the day with two two-week breaks between 6-7 and 13-14 injections). PH conducted electrocautery, removing part of the left lobe of the liver (15-20% by weight of the body) to 65th (and last) day of the introduction of the CCl4. Animals were studied after 65 days of development of CCl4-hepatitis on day 3, 7 and 14 days after laparotomy («falsely operated» animals) and partial hepatectomy. In subcellular fractions of the liver investigated the activity of phosphatdependent glutaminase (FDG), glutamatdehydrogenaze (GDG), glutaminsintetaze (GS), arginase. In the liver tissue investigated the content of ammonia, glutamine, glutamate and urea. Results. Found that on 65-th day of the development of CCl4 in the liver decreases the concentration of ammonia, glutamine, glutamate, urea, and activity of GS, GDG and arginase. Activity FDG was not changed. The use of PH on the background of chronic CCl4-hepatitis has a short-term (3 days) a stimulating effect on the activity FDG, GS, postponed (14 days) the inhibitory effect on the activity of GDG. This was accompanied by an increase in the concentration in the liver of ammonia within 14 days of the postoperative period on the background of maintaining reduced concentrations of glutamine and glutamate it. The stimulatory effect of CHA on the activity of arginase is saved to the 14th day of the postoperative period, however, the concentration of urea in the liver remained below normal. Conclusions. The obtained results show that CGA on the background of chronic hepatitis increases the pathological impact of CCl4 on amniocentesis liver function.

Brown algae are well known as a source of biologically active compounds, especially those having antioxidant activities, such as phlorotannins. In this study we examined the antioxidant activities of crude phlorotannins extracts (CPEs) obtained from Sargassum hemiphyllum (SH) and fractionated according to the molecular weights. When CPEs were administrated at a dose of 30 mg/kg to Kunming mice pre-treated with carbon tetrachloride (CCl4), the levels of oxidative stress indicators in the liver, kidney and brain were significantly reduced in vivo. All the components of various molecular weight fractions of CPEs exhibited greater scavenging capacities in clearing hydroxyl free radical and superoxide anion than the positive controls gallic acid, vitamin C and vitamin E. Particularly, the components greater than 30 kD obtained from ethyl acetate phase showed the highest antioxidant capacities. These results indicated that SH is a potential source for extracting phlorotannins, the algal antioxidant compounds.

Ethnopharmacological Relevance: [corrected] Consortium of yeasts sourced from traditionally used Woodfordia fruticosa flowers proved to be beneficial for fermenting Ashvagandharishta. It resulted in faster fermentation, acceptable organoleptic properties and demonstrable hepatoprotective potential in CCl4 induced hepatotoxicity. To formulate Ashvagandharishta using consortium of yeasts and to investigate its physiochemical parameters. Standardize the formulation with the help of standard withaferin-A and withanolide-A and to evaluate its hepatoprotective potential in CCl4 induced hepatotoxicity in the rat model., Material and Methods: Ashvagandharishta was prepared using a 5% consortium of yeasts and ascertained its quality through physiochemical and phytochemical investigation. Withaferin-A and withanolide-A was simultaneously estimated by HPLC for standardization. Hepatoprotective potential was evaluated by administering 2.31 and 1.15 ml/kg doses while considering biochemical parameters like serum AST, ALT, ALP and lipid profile. Gene expression study was carried out for the expression of antioxidant and inflammatory genes such as CAT, GPx and proinflammatory gene IL-6. Histopathology of liver was also studied with the help of H&E staining., Results: Ashvagandharishta was found organolepticaly acceptable with optimized physiochemical parameters. Withaferin-A and withanolide-A in Ashvagandharishta estimated as 0.3711, 0.7426 (%w/v), respectively. In the CCl4 induced hepato-toxicity model, Ashvagandharishta-2.31ml/kg dose showed significant decrease in elevated hepatic level of AST(p<0.001), ALT(p<0.01) and ALP(p<0.001). Both doses of Ashvagandharishta showed significant reduction of TG, Cholesterol, VLDL and LDL in serum, with corresponding reduction of (p<0.001) serum-HDL. Ashvagandharishta also showed increased serum protein (p<0.05) and albumin (p<0.01) with decrease in bilirubin (p<0.01). Additionally, Ashvagandharishta administration revealed up-regulation in antioxidant genes such as CAT and GPx in liver with concomitant down-regulation in proinflammatory IL-6gene (p<0.01). Histopathological parameters revealed restoration of normal tissue architecture by both doses of Ashvagandharishta., Conclusions: Consortium of yeasts from Woodfordia fruticosa flowers showed better fermentation pattern for Ashvagandharishta produced with acceptable organoleptic properties. Hepatoprotection shown by Ashvagandharishta was mainly through prevention of oxidative damage. Up-regulation of CAT and GPx genes and corresponding down regulation of proinflammatory IL6 gene was revealed as possible mechanism of its action., (© 2013 Elsevier Ireland Ltd. All rights reserved.)

L-arginine may aid in the liver detoxification and may benefit in the treatment of liver disorders such as liver injury. The present study was to investigate the possible protective and curative effects of L-arginine on carbon tetrachloride (CCl(4)) induced hepatotoxicity. Mice received a single dose of CCl(4). L-arginine treatment was given for 6 days prior or post to CCl(4) injection. CCl(4)-intoxication caused marked liver cell necrosis with inflammatory and apoptotic lesions. L-arginine treatment reduced hepatic necrosis and inflammation. CCl(4)-intoxication also enhanced hepatic lipid peroxidation, decreased hepatic GSH level and inhibited the activities of antioxidant enzymes. Pre-treatment and post-treatment with L-arginine decreased lipid peroxidation and restored the antioxidant status to near normal levels. These results suggest that L-arginine administration has hepatoprotective and hepatocurative effects against CCl(4) induced hepatotoxicity in mice., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The present study was carried out to evaluate the antioxidant effect of the chloroform extract of Citharexylum spinosum (CSCE) (Family: Verbenaceae) leaves in Sprague-Dawley male rats. The different groups of animals were administered with carbon tetrachloride (CCl(4); 20% in olive oil, 2 ml/kg body weight) 7 doses (i.p.) at 48 h interval. The CSCE at the doses of 100 and 200 mg/kg or silymarin at a dose of 50 mg/kg were administered intragastrically after 24 h to the CCl(4) treated rats. The effect of CSCE or silymarin on urine and serum markers (urea, creatinine, creatinine clearance, protein, albumin, urobilinogen and nitrite) was measured in CCl(4)-induced nephrotoxicity in rat. Further, the effects on lipid peroxidation (TBARS), enzymatic antioxidants (catalase, superoxide dismutase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase) and non-enzymatic antioxidant glutathione (GSH) were estimated in the kidney samples. The CSCE and silymarin produced significant renal protective effects by restoring the concentration of urine and serum markers. Activity level of antioxidant enzymes and GSH contents were increased while lipid peroxidation (TBARS) was decreased, dose dependently with CSCE and silymarin. Decrease in body whereas increase in kidney weight induced with CCl(4) was restored with CSCE and silymarin. Chemical composition of CSCE indicated the presence of flavonoids, terpenoids, alkaloids and very low amount of saponins. Total flavonoids estimated were (127 ± 14.6) as rutin equivalent mg/g of the extract. From these results, it is suggested that CSCE possesses potent nephroprotective and antioxidant properties., (Copyright © 2010 Elsevier GmbH. All rights reserved.)

Previous studies have indicated that female animals are more resistant to carbon tetrachloride (CCl(4))-induced liver fibrosis than male animals, and that estradiol (E(2)) treatment can inhibit CCl(4)-induced animal hepatic fibrosis. The underlying mechanism governing these phenomena, however, has not been fully elucidated. Here we reported the role of estrogen-induced miRNA-29 (miR-29) expression in CCl(4)-induced mouse liver injury. Hepatic miR-29 levels were differentially regulated in female and male mice during CCl(4) treatment. Specifically, the levels of miR-29a and miR-29b expression were significantly decreased in the livers of male, but not female, mice following 4 weeks of CCl(4) treatment. The down-regulation of miR-29a and miR-29b in male mouse livers correlated with the early development of liver fibrosis, as indicated by increased expressions of fibrotic markers in male mice relative to female mice. In addition, E(2) was maintained at a higher level in female mice than in male mice. In contrast to TGF-β1 that decreased miR-29a/b expression in murine hepatoma IAR20 cells and normal hepatocytes, E(2) enhanced the expression of miR-29a/b through suppression of the nuclear factor-κB (NF-κB) signal pathway, which negatively regulates miR-29 expression. Furthermore, both E(2) treatment and intravenous injection of the recombinant adenovirus expressing miR-29a/b markedly increased the miR-29a/b level and attenuated the expression of fibrotic markers in mouse livers during CCl(4) treatment, supporting the protective role of E(2)-induced miR-29 in CCl(4)-induced hepatic injury. In conclusion, our results collectively demonstrate that estrogen can inhibit CCl(4)-induced hepatic injury through the induction of hepatic miR-29.

Context: Carbon tetrachloride (CCl₄) is frequently used as a chemical inducer of tissue damage. Their effects on mouse peritoneal macrophages and also in peripheral blood lymphocytes are still unknown., Objective: Therefore we tried to focus on intracellular oxidative stress produced by CCl₄ in mouse macrophage and lymphocyte cells., Methods: Intraperitoneal administration of CCl₄ induces intracellular superoxide anions production in mouse macrophages and peripheral blood lymphocytes and leads a subsequent lipid peroxidation and protein oxidation. N-acetyl cystein (NAC) and vitamin C were administered intraperitoneally at a dose of 150 mg/kg and their effect on demodulating the oxidative stress is also checked., Result and Discussion: Several in vitro approaches have already been established as a free radical scavenging models, but this free radical screening models is not always correlated with the in vivo screening models. NAC and vitamin C were administered intraperitoneally and significant reduction of the oxidative stress in term of scavenging of toxic superoxide anion observed in both the macrophages and lymphocytes., Conclusion: Therefore we are hopeful that our work will light a new insight into the screening of in vivo free radical scavenging model for evaluating anti-inflammatory compounds.

In this study, the hepatoprotective effects of hyperoside (1), a flavonoid glycoside isolated from Artemisia capillaris, have been examined against carbon tetrachloride (CCl4)-induced liver injury. Mice were treated intraperitoneally with vehicle or 1 (50, 100, and 200 mg·kg(-1)) 30 min before and 2 h after CCl4 (20 μL·kg(-1)) injection. Levels of serum aminotransferases were increased 24 h after CCl4 injection, and these increases were attenuated by 1. Histological analysis showed that 1 prevented portal inflammation, centrizonal necrosis, and Kupffer cell hyperplasia. Lipid peroxidation was increased and hepatic glutathione content was decreased significantly after CCl4 treatment, and these changes were reduced by administration of 1. Protein and mRNA expression of tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and heme oxygenase-1 (HO-1) and nuclear protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) significantly increased after CCl4 injection. Compound 1 suppressed TNF-α, iNOS, and COX-2 protein and mRNA expression and augmented HO-1 protein and mRNA expression and Nrf2 nuclear protein expression. These results suggest that 1 has protective effects against CCl4-induced acute liver injury, and this protection is likely due to enhancement of the antioxidative defense system and suppression of the inflammatory response.

Aim: To investigate the effect of transgenic expression of kallistatin (Kal) on carbon tetrachloride (CCl(4))-induced liver injury by intramuscular (im) electrotransfer of a Kal-encoding plasmid formulated with poly-L-glutamate (PLG)., Methods: The pKal plasmid encoding Kal gene was formulated with PLG and electrotransferred into mice skeletal muscle before the administration of CCl4. The expression level of Kal was measured. The serum biomarker levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), malonyldialdehyde (MDA), and tumor necrosis factor (TNF)-α were monitored. The extent of CCl4-induced liver injury was analyzed histopathologically., Results: The transgene of Kal was sufficiently expressed after an im injection of plasmid formulated with PLG followed by electroporation. In the Kal gene-transferred mice, protection against CCl4-induced liver injury was reflected by significantly decreased serum ALT, AST, MDA and TNF-α levels compared to those in control mice (P<0.01 to 0.05 in a dose-dependent manner). Histological observations also revealed that hepatocyte necrosis, hemorrhage, vacuolar change and hydropic degeneration were apparent in mice after CCl4 administration. In contrast, the damage was markedly attenuated in the Kal gene-transferred mice. The expression of hepatic fibrogenesis marker transforming growth factor-β1 was also reduced in the pKal transferred mice., Conclusion: Intramuscular electrotransfer of plasmid pKal which was formulated with PLG significantly alleviated the CCl4-induced oxidative stress and inflammatory response, and reduced the liver damage in a mouse model.

The protective in vivo effects of melatonin or pinoline on carbon tetrachloride (CCl(4))-induced oxidative damage were investigated in liver of rats and compared to rats injected only with CCl(4) (5 mL/kg body weight). Hepatic cell membrane fluidity, monitored using fluorescence spectroscopy, exhibited a significant decrease in animals exposed to CCl(4) compared to control rats. Increases in lipid and protein oxidation, as assessed by concentrations of malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA), and protein carbonylation, respectively, were also seen in hepatic homogenates of animals exposed to CCl(4). The administration of melatonin (10 mg/kg body weight) or pinoline injected 30 min before and 1 hr after CCl(4), fully prevented membrane rigidity and protein oxidation. However, treatment with melatonin was more effective in terms of reducing lipid peroxidation than pinoline, as the increases in MDA+4-HDA levels because of CCl(4) were reduced by 93.4% and 34.4% for melatonin or pinoline, respectively. Livers from CCl(4)-injected rats showed several histopathological alterations; above all, there were signs of necrosis and ballooning degeneration. The concurrent administration of melatonin or pinoline reduced the severity of these morphological changes. On the basis of the biochemical and histopathological findings, we conclude that both melatonin and pinoline were highly effective in protecting the liver against oxidative damage and membrane rigidity because of CCl(4). Therefore, these indoles may be useful as cotreatments for patients with hepatic intoxication induced by CCl(4).

The effects of hypoxen on the metabolic processes in the liver tissue have been investigated on experimental animals (rats) with model tetrachloromethane (CCl4) induced toxic liver damage. It is established that the drug decreases the activity of transaminases and lactate dehydrogenase, the total bilirubin level in the blood serum, and the rate of free-radical lipid oxidation in the liver. These effects of hypoxen can be considered as manifestations of the hepatoprotective activity. The efficiency of the drug under conditions of CCl4 intoxication was confirmed by the results of a histological examination.

Carbon tetrachloride (CCl4) is well known to induce hepatotoxicity after being metabolized to trichloromethyl free radical ((.)CCl3) by CYP2E1. In the present study, the hepatotoxicity induced by a single oral dose (2,000 mg/kg) of CCl4 was compared between pregnant (gestation days (GD) 13 and 19) or postpartum (postpartum days (PPD) 1, 13 and 27) and non-pregnant rats. Hepatotoxicity in CCl4-treated pregnant rats evaluated by blood chemistry (alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activities) and histopathological finding (area of damaged hepatocytes) was minimal on GD19, being weaker than that in non-pregnant rats. CYP2E1 expression in non-treated pregnant rats decreased as pregnancy progressed and reached minimum level on GD19. Thus, the degree of CCl4-induced hepatotoxicity roughly corresponded to CYP2E1 levels during pregnancy. After delivery, hepatotoxicity in CCl4-treated lactating rats was maximal on PPD13, being stronger than that in non-pregnant rats, and then it decreased slightly on PPD27. The CYP2E1 level in the non-treated lactating rats tended to increase but remained at lower levels until PPD13 compared with that in non-pregnant rats. Thus, the degree of CCl4-induced hepatotoxicity did not correspond to CYP2E1 levels during lactation. This suggests that during lactation, there may be certain factors other than CYP2E1 expression responsible for the degree of CCl4-induced hepatotoxicity.

Carbon tetrachloride (CCl4) is a model for studying free radical-induced liver injury and screening hepato-protective drugs. Numerous studies have reported the involvement of oxidative stress in CCl4-induced liver damage and the hepato-protective effects mediated by different antioxidants. The present study examined the effects of diphenyl diselenide, (PhSe)2, on hepatotoxicity induced by CCl4 in rats. To this end, male Wistar rats received (PhSe)2 by oral route at the dosage of 31.2 mg/kg for one or two days. After the second day of treatment, rats received CCl4 orally in a single dose. The liver and kidney were utilized for determination of histopathology, biochemical [aspartate (ALT) and alanine (AST) aminotransferases, alkaline phosphatase (ALP), total bilirrubin (TB) and gamaglutamyl transferase (GGT)] and toxicological parameters [thiobarbituric reactive species (TBARS) levels, catalase activity, ascorbic acid, nonprotein thiols (NPSH) and aminolevulinate dehydratase (-ALA-D) activity]. Repeated administration of (PhSe)2 caused a marked potentiation of hepatotoxicity induced by CCl4 exposure, as manifested by an increase in biochemical parameters (AST, ALT, ALP, GGT and BT) and severe alteration in histopathology. This study also demonstrated a potentiation of TBARS levels and a consequent depletion of important antioxidant defenses including catalase and ascorbic acid. Pre-treatment with a single dose of (PhSe)2 prevented the effect of strychnine, a substrate for CYPs, abolishing lethality in mice. This result indicates that (PhSe)2 prevented animal death, suggesting an activator action of (PhSe)2 in CYPs. This study clearly indicates that (PhSe)2 potentiated acute hepatic damage induced by CCl4.

Daily oral administration to rats of probiotic strain Lactobacillus casei 114001 (L.c.) at dose 2,8 x 10(10) cfu/rat during 8 days reduced oxidative stress and liver lesions, induced by a single intraperitoneal administration of carbon tetrachloride (CCl4) at dose 0.5 ml/kg b.w. It was evidenced by several histopathological and biochemical markers, characteristic for CCl4 toroxicity. Membrane damage by toxin was reduced in rats, treated with L.c.: alanine aminotransferase activity in plasma and nonsedimentable activity of lysosomal enzymes in liver were significantly decreased. Treatment with L.c. resulted in partial recovery of activities of antioxidant enzymes and enzymes of xenobiotic metabolism and full recovery of antioxidant capacity of liver cytosol. High level of activity and expression of proteins heme oxygenase and Nrf2 were maintained.

The effects of carbon tetrachloride (CCl(4)) treatment on acute liver damage in knock out (heat shock proteins -- HSP70-/-) mice and wild-type (C57BL/6) mice were examined. Acute liver injury was induced by a single intraperitoneal injection of 0.3 ML/kg CCl(4) in olive oil. Mice were sacrificed at 12, 24, 48 and 72 h after treatment. To assess hepatotoxicity, alanine transaminase, neutrophil infiltration and degree of necrosis were measured. Western blot analysis was employed for heat shock proteins. The result revealed that HSP70-/- mice showed higher alanine transaminase levels and a more severe degree of neutrophilic infiltration and necrosis than those of wild-type mice. Furthermore, HSP70-/- mice recovered more slowly from CCl(4) treatment. In HSP70-/- mice, HSP47 was overexpressed. Therefore, HSP70-/- mice could be an adequate model of acute liver toxicity study.

Possible effect of bone marrow cells on liver regeneration was studied in mice injected with a mixture of hepatotoxins (allyl alcohol and CCl4) in a dose equal to LD50. The mixture of hepatotoxins was used to minimize the restitution regeneration of the liver. The dose of allyl alcohol causing (in combination with CCl4) maximum liver damage was selected beforehand. Increasing the dose of allyl alcohol in the two-component mixture resulted in more severe necrosis of the liver. The maximum dose of alcohol (50 mg/kg) in combination with CCl4 caused irreversible injury to the liver leading to 100% mortality after 2-4 days. In radiation chimeras reconstituted by bone marrow cell transplantation, in which liver damage was induced by a mixture of hepatotoxins containing the maximum dose of allyl alcohol, we observed normalization of liver tissue structure and function. The mechanism of this effect is not clear.

The effects of L-arginine and inhibitors of NO-synthase on the level of stable NO metabolites and nitrosothiols have been investigated under conditions of toxic damage of liver induced by CCl4. The L-arginine improved resistance of hepatic cells to damaging action of tetrachloromethane, but inhibition of NO-synthase increased hepatotropic action of CCl4. The existence of some base level of nitrosothiols, acting as a reserve pool of nitric oxide in organism, has been supposed.

Propolis (bee glue), a resinous wax-like beehive product has been used since ancient times for its pharmaceutical properties. In the present study, the ethanolic extract of propolis (50, 100, 200 and 400 mg/kg, p.o.) was studied for its hepatoprotective activity against carbon tetrachloride (CCl4, 1.5 ml/kg, i.p.) induced liver damage in rats. Administration of CCl4 caused a sharp elevation in the activity of serum transaminases, serum alkaline phosphatase, acid phosphatase and hepatic lipid peroxidation (LPO) levels, and a significant decrease in the ATPase, alkaline phosphatase and succinic dehydrogenase activities in the liver and kidney and hepatic GSH level. The treatment with propolis extract at the doses of 200 and 400 mg/kg significantly reversed the various biochemical alterations in blood, liver and kidney induced by CCl4 intoxication. The hepatoprotective property of propolis may be due to its antioxidant activity.

Introduction: The purpose of this study was to optimize carbon tetrachloride-induced hepatotoxicity in the rat with respect to dose, route of injection, and time course., Methods: Male Wistar albino rats, 4 to 6 weeks old and weighing 130-180 g were used. Hepatotoxicity was evaluated by measuring the activity of serum enzymes (alkaline phosphatase [ALP], alanine aminotransferase [ALT], and aspartate aminotransferase [AST]) as well as serum total bilirubin level., Results: Intraperitoneal injection of carbon tetrachloride (CCl(4)) increased the activity of ALP (from 64.9 to 137.3 U/l), ALT (from 106.6 to 693.1 U/l), and AST (from 113.8 to 693.9 U/l). Plasma bilirubin level increased (from 0.119 to 0.42 mg/dl). In contrast, subcutaneous injection of CCl(4) had no effect on these variables. The optimum intraperitoneal dose of CCl(4) was found to be 2 ml/kg body weight (dissolved in an equal volume of olive oil), and this increased the level of bilirubin and the activity of the three enzymes significantly, without causing death of the animals. Hepatotoxicity was observed within 2 h of intraperitoneal injection of CCl(4) and reached a peak after 24 h. Bilirubin level and serum enzyme activities declined gradually to normal levels by 3 days after CCl(4) injection., Conclusion: It is possible to reliably evoke reversible hepatotoxicity in rats by intraperitoneal injection of 2 ml/kg CCl(4).

The involvement of NF-kappa B binding activity is known to be important in the mechanism of acute liver injury and in the induction of cyclooxygenase (COX-2). This study was performed to evaluate NF-kappa B binding activity and the expression of COX-2 in chronic liver injury induced by carbon tetrachloride (CCl(4)). Liver tissues from Sprague-Dawley rats were collected at 1, 3, 5, and 7th week after intraperitoneal injection of 0.1 mL of CCl(4)/100 g body weight twice a week. Reactive oxy-gen species (ROS) were measured in the postmitochondrial fraction by dichlorofluorescein formation with a fluorescent probe. An electrophoretic mobility shift assay was performed for NF-kappa B binding activity. Western blot was performed to measure the level of COX-1, COX-2, p65, p50, and I B proteins. ROS and NF-kappa B activity increased during the CCl4-induced chronic liver injury. The expression of nuclear p65 protein and p50 protein increased compared with that of the control, while the cytoplasmic I B protein decreased as the inflammation persisted. The expression of COX-2 in CCl(4)-treated rat liver increased compared with that of the control. It could be suggested that ROS produced by CCl(4) treatment increased NF-kappa B binding activity and thereby COX-2 expression, and these might be implicated in the progress of chronic liver damage.

Microsomal fractions from rat liver were examined by means of Fourier transform IR (FTIR) spectroscopy to study the in vivo toxic effect of carbon tetrachloride administered by intraperitoneal injection. Lipid content was significantly enhanced in the liver of treated rats compared with untreated ones. The level of saturated fatty acids largely increased while that of unsaturated acids slightly decreased as a consequence of lipid peroxidation induced by the xenobiotic compound. The conformational structure of membrane proteins was changed, which was shown by the large decrease in the alpha-helical configuration. In the polysaccharide region we observed an important loss in glucidic structures that could be related to the metabolic changes caused by carbon tetrachloride intoxication. Thus, FTIR spectroscopy appears to be a useful tool to rapidly investigate the chemical alterations induced by this drug in liver microsomes and to correlate them with biochemical and physiological data.

Background/aims: The effects of colchicine on acute liver injury induced by carbon tetrachloride or by dimethylnitrosamine in mice were examined., Methods: Nonlethal acute liver injury was induced in male BALB/c mice by a single intraperitoneal injection of 0.8 ml/kg carbon tetrachloride or 15 mg/kg dimethylnitrosamine. 0.6 mg/kg colchicine was administered 18 h or 2 h intraperitoneally before hepatotoxin treatment., Results: Reversible centrilobular to mid-zone necrosis and apoptosis occupying half the liver lobular area was evoked by carbon tetrachloride, and dimethylnitrosamine, respectively. Administration of colchicine 18 h before hepatotoxins markedly suppressed liver injury, whereas colchicine administration 2 h before the hepatotoxins accelerated it. The hepatoprotective effect evoked by colchicine was due to reduction in liver cytochrome P450 content and P450 2E1 activity. In contrast, the hepatodestructive effect seen in the carbon tetrachloride model was related to the extent of lipid peroxidation promoting plasma membrane destruction, while the hepatodestructive effect in the dimethylnitrosamine model was due to suppression of Bcl-X(L) expression, leading to acceleration of apoptosis., Conclusions: A biphasic effect of colchicine on carbon tetrachloride- and dimethylnitrosamine-induced acute liver injury was seen. The time interval between colchicine administration and the hepatotoxin treatment is crucial to the subsequent development of liver lesions.

CYP2E1 knockout mice (cyp2e1-/-) were used to investigate the involvement of CYP2E1 in the development of carbon tetrachloride (CCl4)-induced hepatotoxicity. Male cyp2e1-/- and wild-type (cyp2e1+/+) mice were given a single i.p. injection of 1 ml/kg (= 1.59 g/kg) CCl4 and 24 h later liver injury was assessed by elevations of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and histopathology. No significant increases in serum ALT and AST activities were observed in cyp2e1-/- mice when compared to wild-type counterparts after CCl4 exposure. No detectable abnormality in liver histology was found in cyp2e1-/- mice after CCl4 exposure. In contrast, CCl4 treatment resulted in 442- and 125-fold increases in serum ALT and AST activities, respectively, in wild-type mice. Consistent with the results of serum ALT and AST activities, severe hepatic damage was noted in livers of wild-type mice, indicating the importance of CYP2E1 in mediating the hepatic damage following CCl4 exposure in these mice. In addition, a dramatic decrease in CYP2E1-catalyzed p-nitrophenol activity and complete loss of immunoreactive CYP2E1 were observed in wild-type mice after CCl4 treatment, suggesting that CYP2E1 was degraded during the process of CCl4-induced hepatotoxicity. These studies conclusively demonstrate that CYP2E1 is the major factor involved in the CCl4-induced hepatotoxicity in mice.

A histopathological evaluation was performed on liver of rats treated with carbon tetrachloride (CCl4) and 25,50 and 100 mg/kg of Cuban red propolis (RP) extract. Additionally, alanine aminotransferase (ALT) in serum and liver triglycerides were determined in all animals. The morphometric study included the count of ballooned cells at the zone III of the Rappaport acini and the assessment of a software program to estimate the extension of steatosis area. A significant reduction of ballooned cells count in liver was observed at three dose levels of RP extract with respect to rats treated only with CCl4. Also, a certain reduction of steatosis degree as well as decreased concentration of liver triglycerides and ALT activity were found in three groups of rats treated with RP extract and CCl4 in relation to those treated with the hepatotoxin. Taken together, the histopathological and biochemical findings show hepatoprotective effects of RP extract in CCl4-induced liver damage in rats, probably due to the antioxidant effect of RP.

Sixty C3H/He male mice were divided into 6 groups (10 mice per group). Control mice (group I) received three injections of PBS and drinking water. Mice of group II were injected with PBS but drinking water was substituted by ethanol solutions with increasing concentration of ethanol (w/v): 6% during the first week of experiment, 10% during the second and 20% during the third week. Group III received three intraperitoneal injections of CCl4 (1 ml of CCl4 per 1 kg of body weight) and water for drinking. Group IV was treated with CCl4 as group III, but drinking water was substituted by ethanol solutions with increasing concentrations as in the group II. Samples of blood, liver and spleen were taken 24 h after the third acute CCl4 intoxication. Group IIIa and IVa were treated as group III and IV, respectively, but samples of blood and organs were taken a week after the last CCl4 injection. A typical increase in serum ALT and necrosis of hepatocytes as confirmed by the histological examination, was observed 24 h after CCl4 injections (group III and IV). A week later (group IIIa and IVa) regenerative changes in the liver and a significant decrease in ALT serum activity was observed. Acute CCl4 intoxication (group III) significantly decreased IFN production in liver and spleen cells isolated 24 h after the last CCl4 injection. Combined CCl4 and ethanol administration affected very strongly IFN production (group IV).(ABSTRACT TRUNCATED AT 250 WORDS)

1. A short-term CCl4 administration was used in vivo as a model to produce a rise in lactic acid levels and to explain the probable interaction of CCl4 and lactic acid elevation with hepatic fibrogenesis. 2. A single dose of CCl4 produced an increase in lactic acid levels from 16.6 +/- 3.57 to 24.2 +/- 4.2 mg/dl. Three consecutive doses produced an elevation to 33.28 +/- 10.07 mg/dl, thus describing a direct relationship between lactic acid levels and CCl4 administration in a short-term fashion. 3. A morphological evaluation was performed to show hepatic changes caused by CCl4 administration. No clue of fibrogenesis was found. However, we conclude that an elevation in lactic acid exists, prior to cirrhosis. Therefore, chronic presence of lactic acid may lead to cirrhosis.

Thioridazine (TDZ) administration to rats (50 mg/kg i.p.) 6 or 10 h after CCl4 treatment (1 ml/kg in olive oil i.p.) partially prevented necrogenic effects of this compound at 24 h but not at 72 h. TDZ did not have inhibitory effects on CCl4 activation, covalent binding (CB) of reactive metabolites to cellular constituents or CCl4-induced lipid peroxidation (LP). Moreover, TDZ had enhancing effects on both LP and CB. TDZ was able to increase protein and phospholipid synthesis and slightly but significantly enhanced protein but not phospholipid degradation in livers from control rats. TDZ administration decreased calcium liver content in CCl4-poisoned animals but did not change the intensity of CCl4-induced fatty liver. TDZ lowered body temperature in CCl4-treated animals during the 24 h observation period. These results and previous studies from our laboratory suggest calcium and calmodulin (CaM) participation in the CCl4 necrogenic effects on the liver but not in the hepatotoxin-induced fatty liver. TDZ-lowering effects on body temperature might also be a determinant in the delaying effects of this drug on the onset of CCl4-induced necrosis. Present experiments did allow discrimination between these two or other possible mechanisms for TDZ modulation effects.

Oral administration of carbon tetrachloride to rats or mice caused striking decreases in rat lung microsomal cytochrome P-450 and benzphetamine demethylase activity and in the enzyme-mediated covalent binding of 4-ipomeanol in preparations of rat and mouse lung microsomes, mouse lung slices and isolated whole-mouse lungs. Although it is not yet known whether cytochrome P-450 and benzphetamine demethylase activities are present in substantial amounts in more than one lung cell type in mice or rats, previous studies have indicated that cytochrome P-450 enzymes located in pulmonary bronchiolar Clara cells of these mediate the covalent binding of 4-ipomeanol to lung macromolecules. Histologic examinations of lungs of animals given doses of CCl4, orally or by inhalation, revealed striking morphologic changes in Clara cells, including severe dilation of endoplasmic reticulum and occasional cellular necrosis. Because of cytochrome P-450 enzymes are capable of mediating the formation of highly reactive and potentially toxic-free radicals from CCl4, the present results support the view that pulmonary Clara cells are susceptible to CCl4-induced injury due to their capacity to metabolically activate the chemical.

Male Wistar rats weighing 190-200 g were fed a low protein diet. Atrophy of cytoplasm was observed after a 3-week malnutrition. In early periods of liver regeneration (6 hr after CCl4 poisoning), an increase in DNA synthesis was accompanied by an increase in summary concentration of organelle membranes. Though their ploidy was higher than in the control, volume of hepatocytes and summary area of organelles surface membrane was smaller than in standard diet. These data show a reduced capacity for realization of genetic program during the regeneration period in protein-deficient rats.

Potentiation of haloalkane hepatotoxicity by ketones and ketogenic agents is a well-known phenomenon. The importance of the CCl4 dosage in these combinations, however, has not been explored. Its influence was investigated in male Sprague-Dawley rats. Dose-effect curves for potentiation were generated using 1,3-butanediol, methyl n-butyl ketone or methyl isobutyl ketone as potentiation agents. Animals were orally treated with these compounds prior to a challenge of CCl4 (0 to 0.5 ml/kg, ip). Liver injury was assessed by monitoring plasma ALT activity and bilirubin concentrations after CCl4 treatment. The minimal effective dosage (MED) for each potentiator was used as the criterion of comparison for each combination. The MED values were determined from the plasma ALT data. Results showed that when the CCl4 dosage was increased from 0.01 to 0.10 ml/kg, the MED of each potentiator decreased 10-fold. For a given potentiator, the product of the CCl4 dosage (H, "hepatotoxicant") by the corresponding MED value (P, "potentiator") remained the same in this range of CCL4 dosages. The severity of the liver injury was similar. These findings suggest that a given level of liver injury induced by a ketone/haloalkane combination could be evaluated on the basis of the [P X H] product.