Protective effect of (S)-bakuchiol from Psoralea corylifolia on rat liver injury in vitro and in vivo

The aim of this study was to investigate the protective effect of (S)-bakuchiol isolated from the seed of Psoralea corylifolia, on liver injury. Primary rat hepatocyte intoxication was induced by tert-butyl hydroperoxide (tBH), carbon tetrachloride (CCl4) or D-galactosamine (D-GalN). Liver injury was induced by either CCl4 or D-GalN in rats. In vitro, the cellular leakage of lactate dehydrogenase and cell viability following treatment with hepatotoxicants were significantly improved by bakuchiol treatment at a concentration range of 25-200 microM for tBH, 100-200 microM for CCl4 and 100-200 microM for D-GalN-induced hepatocyte injury. Treatment with bakuchiol significantly inhibited lipid peroxidation and intracellular glutathione depletion in hepatocytes induced by tBH, CCl4 or D-GalN. Treatment with bakuchiol (25 or 50 mg/kg, p.o.) at 1, 24 and 48 h after subcutaneous injection of CCl4 significantly reduced the levels of aspartate transaminase and alanine transaminase in serum. Histological observations revealed that fatty acid changes, hepatocyte necrosis and inflammatory cell infiltration in CCl4-injured liver was improved when treated with bakuchiol. Bakuchiol treatment (25 and 50 mg/kg, p.o.) also significantly reduced the levels of aspartate transaminase and alanine transaminase in an acute liver injury model induced by D-GalN. From these results, bakuchiol has a protective effect against tBH, CCl4 or D-GalN-induced hepatotoxicity in vitro or in vivo.     

Acanthoic acid from Acanthopanax koreanum protects against liver injury induced by tert-butyl hydroperoxide or carbon tetrachloride in vitro and in vivo

The aim of this study was to investigate the protective effect of acanthoic acid, a diterpene isolated from the root bark of Acanthopanax koreanum, on liver injury induced by either tert-butyl hydroperoxide (tBH) or carbon tetrachloride in vitro and in vivo. In vitro, the cellular leakage of lactate dehydrogenase (LDH) following treatment with 1.5 mM tBH for 1 h, was significantly inhibited by co-treatment with acanthoic acid (25 and 5 microg/mL) and the ED (50) of acanthoic acid was 2.58 microg/mL (8.5 microM). The cellular leakage of LDH following one hour of treatment with 2.5 mM CCl (4) was significantly inhibited by co-treatment with acanthoic acid (25 microg/mL) and the ED (50) of acanthoic acid was 4.25 microg/mL (14.1 microM). Co-treatment with acanthoic acid significantly inhibited the generation of intracellular reactive oxygen species (ROS) and intracellular glutathione (GSH) depletion induced by tBH or CCl (4). Acanthoic acid pretreatment (100 mg/kg per day for four consecutive days, p. o.) significantly reduced levels of aspartate transaminase and alanine transaminase in acute liver injury models induced by either tBH or carbon tetrachloride. Treatment with acanthoic acid (100 mg/kg, p. o.) at 6, 24, and 48 hours after carbon tetrachloride subcutaneous injection significantly reduced the levels of aspartate transaminase and alanine transaminase in serum. Histological observations revealed that fatty acid changes, hepatocyte necrosis and inflammatory cell infiltration in CCl (4)-injured liver were improved upon treatment with acanthoic acid. In vivo treatment with acanthoic acid was not able to modify CYP2E1 activity and protein expression in liver microsomes at the dose used, showing that the hepatoprotective effect of acanthoic acid was not mediated through inhibition of CCl (4) bioactivation. From the results above, acanthoic acid had a protective effect against tBH- or CCl (4)-induced hepatotoxicity in vitro and in vivo.     

鹅不食草煎液对小鼠肝损伤的保护作用

目的:观察鹅不食草煎液对小鼠3种肝损伤模型的保护作用.方法:采用四氯化碳(CCl4)、对乙酰氨基酚(APAP)、D-氨基半乳糖 脂多糖(D-GalN LPS)致3种小鼠肝损伤模型,测定血清谷丙转氨酶(ALT).结果:鹅不食草煎液能明显降低CCl4,APAP,D-GalN LPS引起的肝损伤后小鼠血清中升高的ALT水平.结论:鹅不食草煎液对实验性肝损伤有明显的保护作用.     

The carbon dioxide anion radical adduct in the perfused rat liver: relationship to halocarbon-induced toxicity

CCl4 has been shown previously to be metabolized to the trichloromethyl radical (.CCl3) and to a novel oxygen-containing carbon dioxide anion radical (.CO2-) in the perfused rat liver and in vivo. Since the role of free radicals in CCl4-induced hepatotoxicity is unclear, these studies were designed to determine if a relationship between .CO2- formation and halocarbon-induced hepatotoxicity exists. CCl4 or bromotrichloromethane (CBrCl3) was infused into livers from control or phenobarbital-treated rats perfused with either nitrogen- or oxygen-saturated Krebs-Henseleit bicarbonate buffer. Samples of effluent perfusate and chloroform/methanol extracts of liver were analyzed by ESR spectroscopy for free radical adducts following infusion of halocarbon and the spin trap, phenyl-t-butylnitrone (PBN). Hyperfine coupling constants and 13C-isotope effects observed in the ESR spectra of organic extracts of liver demonstrated the presence of the PBN radical adduct of .CCl3 from both halocarbons. Radical adducts in aqueous extracts of liver and effluent perfusate had hyperfine coupling constants and 13C-isotope effects identical to those of PBN/.CO2- generated chemically from formate. The PBN/.CO2- radical adduct was also observed in urine following the intragastric administration of CBrCl3 and PBN. Detection of PBN/.CO2- adducts in the effluent perfusate was decreased 3- to 4-fold by DIDS (0.2 mM), an inhibitor of the plasma membrane anion transport system. The rate of formation of PBN/.CO2- was decreased 2- to 3-fold following inhibition of cytochrome P-450-dependent monooxygenases by metyrapone (0.5 mM) and was increased about 2-fold by induction of cytochrome P-450 by phenobarbital pretreatment. Toxicity of halocarbons in the perfused liver was assessed by measuring the release of lactate dehydrogenase (LDH) into the effluent perfusate in livers from phenobarbital-treated rats under conditions identical to those employed to detect radical adducts (i.e., during the infusion of CCl4 or CBrCl3 into livers perfused with either nitrogen- or oxygen-saturated perfusate). Under all conditions studied, PBN/.CO2- was detected in the effluent perfusate within 2-4 min. Metabolism of halocarbons to PBN/.CO2- was 6- to 8-fold faster during perfusion with nitrogen-saturated rather than with oxygen-saturated perfusate. Concomitantly, liver damage detected from LDH release occurred much sooner during halocarbon infusion in the presence of nitrogen-saturated rather than oxygen-saturated perfusate. A good correlation between the rate of formation of PBN/.CO2- and the time of onset of LDH release following halocarbon infusion was observed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Du-Zhong (Eucommia ulmoides Oliv.) leaves inhibits CCl4-induced hepatic damage in rats.

The protective effects of water extract of Du-Zhong (Eucommia ulmoides Oliv.) leaves (WEDZ) and its active compound (protocatechuic acid; PCA) on liver damage were evaluated by carbon tetrachloride (CCl4)-induced chronic hepatotoxicity in rats. Wistar rats were orally treated with WEDZ (0.1, 0.5, and 1.0 g/kg bw) or PCA (0.1 g/kg bw) with administration of CCl4 (0.5 ml/rat, 20% CCl4 in olive oil) for 28 consecutive days. It showed that CCl4-treated rats increased the relative organ weights of liver and kidney. CCl4-induced rats liver damage and significantly (p<0.05) increased the GOT, GPT, LDH and ALP levels in serum as compared with the control group. Treatment with WEDZ or PCA could decrease the GOT, GPT, LDH and ALP levels in serum when compared with CCl4-treated group. CCl4-treated rats also significantly (p<0.05) decreased the GSH content in liver and trolox equivalent antioxidant capacity (TEAC) in serum whereas increased (p<0.05) MDA content in liver as compared with the control group. Treatment with WEDZ or PCA also significantly (p<0.05) increased the GSH content and significantly (p<0.05) decreased the MDA content in liver. Administration of WEDZ or PCA could increase the activities of GPx, GRd and GST in liver. Liver histopathology showed that WEDZ or PCA reduced the incidence of liver lesions including hepatic cells cloudy swelling, lymphocytes infiltration, cytoplasmic vacuolization, hepatic necrosis and fibrous connective tissue proliferated induced by CCl4 in rats. The data suggest that oral administration with WEDZ for 28 consecutive days significantly decrease the intensity of hepatic damage induced by CCl4 in rats.     

Effect of matrine hydrochloride on liver injury

Objective Searching the function that the Injection of the matrine hydrochloride prevents and cures acute chemical liver injury of mice、immunity liver injury of mice and chronic liver injury of rats.Methods Acute hepatic injury models of mice induced by Chemical poison carbon tetrachloride(CCl4),thioacetamide(TAA),D-galactosamine(D-GalN),immunity hepatic injury model of mice induced by BCG and fat polysaccharide(LPS),chronic liver injury model of rats induced by CCl4 were introduced in the experiment.The serum ALT and AST were measured in acute hepatic injury experiments.Serum ALT,AST,AKP,ALB,TP,BiL-T,creatinine,triglyceride,sialic acid,laminin,hyaluronic acid,type Ⅲ procollagen and type Ⅳ collagen,hepatic hydroxyproline(HyP)of rats in chronic liver injury animals were determined after Injection of the matrine hydrochloride.Results The Injection of the matrine hydrochloride reduced serum ALT and AST level of acute chemical liver injury of mice induced by CCl4,TAA and D-GalN.The index of the liver and the spleen of immunity liver injury of mice induced by BCG and LPS were decreased after the injection of matrine hydrochloride treatment.Compared with the model group,the injection may obviously inhibited serum ALT,AST,TP,AKP,TRI,BiL-T,creatinine,triglyceride,sialic acid,laminin,hyaluronic acid,type Ⅲ procollagen and type Ⅳ collagen activity of chronic liver injury of rats induced by CCl4,elevated ALB、A/G,reduced the liver HyP,decreased the index of the liver and the spleen.The liver visual observation,the pathology inspection and the HAI grading result showed the injection may reduce the inflammatory activity in liver tissue,restrain the liver cell damage,reduce the pseudolobuli formation.Conclusions The Injection of matrine hydrochloride had the protective function to acute chemical hepatic injury of mice induced by CCl4、TAA、D-GalN、immunity hepatic injury of mice induced by the BCG and LPS and chronic liver injury of rats induced by CCl4.     

Individual serum bile acids as early indicators of carbon tetrachloride- and chloroform-induced liver injury.

Individual serum bile acids (SBA) are emerging as potentially useful early indicators of liver injury. This study was undertaken to compare the usefulness of individual SBA with the routinely used assays for detecting the effects of the hepatotoxicants carbon tetrachloride (CCl4) and chloroform (CHCl3). Serum samples were assayed for liver injury by determination of alanine aminotransferase (ALT), aspartate amino-transferase (AST), alkaline phosphatase (ALP), bilirubin and total bile acid (by enzymatic kit). These results were compared with levels of individual SBA measured by high performance liquid chromatography (HPLC). Liver samples from CCl4-treated rats were taken for light and electron microscopic examination. The highest dose for each chemical caused increases in serum ALT and AST but not ALP. Chloroform at the highest dose increased bilirubin. Total SBA levels as assayed by the kit were elevated in response to CCl4 and CHCl3 at doses below which serum enzymes and bilirubin were increased. Some individual SBA were increased at a still lower dose for each of these two chlorinated solvents. At the lowest dose of CCl4 tested no consistent light microscopic or ultrastructural changes were found. At all the higher doses periacinar cells displayed typical accumulation of lipid droplets and degranulation and dilation of rough endoplasmic reticulum. The extent of the ultrastructural changes were dose-dependent. Thus individual SBA assayed by HPLC may be considered as a very sensitive indicator of liver injury induced by the classical hepatotoxicants carbon tetrachloride and chloroform.     

A CCl4/CHCl3 interaction study in isolated hepatocytes: non-induced and phenobarbital-pretreated cells

The purpose of this study was to evaluate an isolated hepatocyte model for predicting the in vivo hepatotoxicity of carbon tetrachloride (CCl4) and chloroform (CHCl3), alone and in combination. Response surface methodology (RSM) was used to analyze and describe the data. The interaction was evaluated for % initial K+ (cell injury) and % LDH leakage (cell death) in non-induced (untreated) and phenobarbital-pretreated suspended hepatocytes. CCl4 and CHCl3 were delivered alone and in combination in dimethyl sulfoxide (DMSO) to suspended hepatocytes. The maximum observed no-effect level (MONEL) for CCl4 in non-induced cells was 1.0 mM (LDH and K+). In induced cells, the MONEL was 0.25 mM (K+) and 0.5 mM (LDH). The MONEL for CHCl3 in non-induced cells was 5.0 mM (LDH and K+) and in induced cells was 0.5 mM (K+) and 1.0 mM (LDH). Phenobarbital pretreatment enhanced the toxicity of both CCl4 and CHCl3, alone and in combination. RSM analysis of the % initial K+ and % LDH for CCl4 and CHCl3 in combination in noninduced and induced cells showed a greater than additive interaction. The isolated hepatocyte model appears to be a promising system for evaluating the toxicity of chemical mixtures and predicting their in vivo effects.     

Protective effect of L-carnitine and coenzyme Q10 on CCl₄-induced liver injury in rats

This study provides an information about the mechanisms of liver injury induced by CCl(4), and determines the influence of administration of L-carnitine or/and CoQ10 as prophylactic agents against CCl(4) deteriorative effect. The study was carried out on 80 adult male albino rats divided into eight groups, 10 animals each, as follows: four normal groups (control, treated with L-carnitine, treated with CoQ10, and treated with a combination of Lcarnitine and CoQ10) and four liver injury groups treated with CCl(4) (control, treated with L-carnitine, treated with CoQ10, and treated with a combination of L-carnitine and CoQ10). Liver injury was induced by s.c. injection of a single dose of CCl(4) (1 ml/kg). L-carnitine (50 mg/kg/day) was given i.p. for four successive days 24 hours before CCl(4) injection, and CoQ10 (200 mg/kg) was given as a single i.p. dose 24 hours before CCl(4) injection. Animals were sacrificed 24 hours after CCl(4) injection, blood samples were withdrawn and liver tissue samples were homogenized. The levels of the following parameters were determined: hepatic reduced glutathione, serum ALT and AST, hepatic lipid peroxides, hepatic vitamin C, hepatic and serum total protein, serum albumin, serum sialic acid, serum nitrite, and serum and hepatic total LDH activities and LDH isoenzymes. The obtained data revealed that CCl(4) injection produced a significant decrease in reduced glutathione content, vitamin C, total protein and albumin levels. However, there was a significant increase in serum ALT and AST activities, lipid peroxides, sialic acid, nitric oxide, serum and hepatic total LDH activities. On the other hand, groups treated with L-carnitine or/and CoQ10 prior to CCl(4) injection showed an improvement in most parameters when compared with cirrhotic control group. It has been concluded that L-carnitine and coenzyme Q10 have a pronounced prophylactic effect against liver damage induced by halogenated alkanes such as carbon tetrachloride.     

护肝降酶口服液对小鼠急性肝损伤的保护作用

目的：探讨护肝降酶口服液(HGJMKFY)对小鼠急性肝损伤的保护作用。方法：采用四氯化碳(carbontetrachloride,CCl4)、D-半乳糖胺(D-galactosamine,D-GaIN)复制小鼠急性肝损模型。给予护肝降酶口服液(分大、小剂量组),并设联苯双酯阳性对照及空白对照组。测定血清中丙氨酸氨基转移酶(alanineaminotransferase,ALT)、天门冬氨酸氨基转移酶(aspartate aminotransferase,AST)的水平。结果：护肝降酶口服液36g/kg剂量组对CCl4所致的小鼠急性肝损ALT和AST升高有明显降低作用;其36g/kg和18g/kg剂量组对D-半乳糖胺所致的小鼠急性肝损血清ALT和AST的升高均有明显降低作用。结论：护肝降酶口服液对CCl4、D-GaIN所致小鼠急性肝损伤有一定保护作用。     

Differences in the response of hepatic and intestinal drug metabolizing enzymes in rats following carbon tetrachloride and/or phenobarbital treatment

The activities of the microsomal drug metabolizing enzymes in the liver and intestinal mucosa of rats were studied after the intraperitoneal administration of carbon tetrachloride and/or subcutaneous phenobarbital administration. The membrane phospholipid content was decreased after carbon tetrachloride treatment indicating destruction in the membrane structure. Aryl hydrocarbon hydroxylase activity was decreased in the liver and intestinal mucosa after treatment with CCl4 alone and in combination with phenobarbital. The CCl4 treatment increased the intestinal epoxide hydratase activity but decreased the activity in the liver. The hepatic UDPglucuronosyltransferase was slightly induced by phenobarbital and the activity was elevated by the CCl4 treatment. In the intestinal mucosa the enhanced UDPglucuronosyltransferase activity was observed only after phenobarbital pretreatment and the activity was decreased by CCl4. These results support the view that epoxide hydratase and UDPglucuronosyltransferase enzymes occupy different locations in the endosplasmic reticulum of intestinal mucosa than of liver.     

Scutellaria baicalensis inhibits liver fibrosis induced by bile duct ligation or carbon tetrachloride in rats

This study was carried out to investigate the antifibrotic effects of methanol extracts from the traditional Chinese medicinal herb, the root of Scutellaria baicalensis Georgi, on liver fibrosis induced by bile duct ligation and scission (BDL) or carbon tetrachloride (CCl4) in rats. Liver fibrosis was assessed by histological observations and by measuring levels of liver hydroxyproline, lipid peroxidation based on malondialdehyde (MDA) production, and serum enzyme activities. The morphological characteristics of livertissuewere examined by Masson'strichrome staining and immunostaining against smooth muscle cell alpha-actin. In both models, the levels of hydroxyproline and MDA in liver were significantly increased. Treatment with a methanol extract of S. baicalensis significantly reduced the levels of liver hydroxyproline and MDA, with improved histological findings. In both models, the liver areas positive for smooth muscle cell alpha-actin were considerably decreased by treatment with oral methanol extract of S. baicalensis (150 mg kg(-1) daily for 28 days). A methanol extract of S. baicalensis root inhibits fibrosis and lipid peroxidation in rat liver induced by BDL or CCl4.     

Protective effect of glycoprotein isolated from Ulmus davidiana Nakai on carbon tetrachloride-induced mouse liver injury

This study was carried out to evaluate the hepatoprotective activity of glycoprotein isolated from the stems of Ulmus davidiana Nakai (UDN), which has been used as an anti-inflammatory agent in folk medicine. We evaluated lipid peroxidation in glucose/glucose oxidase (G/GO)-induced BNL CL.2 cells and measured thiobarbituric acid reactive substances (TBARS), lactate dehydrogenase (LDH), nitric oxide (NO), antioxidant enzyme (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)), activity of cytotoxic-related signals (hepatic cytochrome c, nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1)) and levels of plasma lipids (triglyceride (TG) and total cholesterol (TC)) in carbon tetrachloride (CCl(4,) 1.0 mL kg(-1))-induced A/J mouse. The results in G/GO-induced BNL CL.2 cells showed that UDN glycoprotein had a dose-dependent inhibitory effect on lipid peroxidation. The results in carbon tetrachloride (CCl(4,) 1.0 mL kg(-1))-induced A/J mouse indicated that treatment with UDN glycoprotein (40 mg kg -1) lowered LDH activity and TBARS formation, and increased NO production and antioxidant enzymes activity, compared with control. Also, our finding from CCl(4)-treated mice after pretreatment with UDN glycoprotein demonstrated that the activity of cytotoxic-related signals decreased but the levels of plasma lipids increased, compared with CCl(4) treatment alone. Here, we speculate that UDN glycoprotein has a protective character to CCl(4)-induced mouse liver injury.     

Protective effect of malotilate (diisopropyl 1,3-dithiol-2-ylidenemalonate) on carbon tetrachloride-induced liver injury in mice and rats

The protective effect of malotilate was studied on the liver injury induced by carbon tetrachloride (CCl4) in mice and rats. Plasma GOT and GPT activities were used as indices for the liver injury, and the liver was histopathologically examined. A remarkable suppressing effect on the liver injury was observed when malotilate was orally given 6 hr prior to oral administration of CCl4 in mice and 3, 6 or 12 hr in rats. Malotilate was also effective in preventing the liver injury caused by intraperitoneal injection of CCl4, indicating that the protective effect is not derived from the decreased CCl4 absorption. The liver injury was suppressed even when malotilate was given 12 or 24 hr prior to oral administration of CCl4 in mice and 24, 48 or 72 hr in rats. It may be the characteristic of malotilate that the protective effect lasts for a long period. It is supposed that the effect is due not only to the inhibition of the metabolic activation of CCl4 but also the other action(s) of malotilate.     

Aloe-Emodin quinone pretreatment reduces acute liver injury induced by carbon tetrachloride

Aloe contains several active compounds including aloin, a C-glycoside that can be hydrolyzed in the gut to form aloe-emodin anthrone which, in turn, is auto-oxidized to the quinone aloe-emodin. On the basis of the claimed hepatoprotective activity of some antraquinones, we studied aloe-emodin in a rat model of carbon tetrachloride (CCl4) intoxication, since this xenobiotic induces acute liver damage by lipid peroxidation subsequent to free radical production. Twelve rats were treated with CCl4 (3 mg/kg) intraperitoneally and six were protected with two intraperitoneally injections of aloe-emodin (50 mg/kg; CCl4+aloe-emodin); six other rats were only aloe-emodin injected (aloe-emodin) and six were untreated (control). Histological examination of the livers showed less marked lesions in the CCl4+aloe-emodin rats than in those treated with CCl4 alone, and this was confirmed by the serum levels of L-aspartate-2-oxoglutate-aminotransferase (394+/-38.6 UI/l in CCl4, 280+/-24.47 UI/l in CCl4+aloe-emodin rats; P<0.05). We also quantified changes in hepatic albumin and tumour necrosis factor-alpha mRNAs. Albumin mRNA expression was significantly lower only in the liver of CCl4 rats (P<0.05 versus control) and was only slightly reduced in the CCl4+aloe-emodin rats. In contrast tumour necrosis factor-alpha mRNA was significantly higher (P<0.05) in the CCl4 than the control rats and almost equal in the CCl4+aloe-emodin, aloe-emodin and control groups. In conclusion, aloe-emodin appears to have some protective effect not only against hepatocyte death but also on the inflammatory response subsequent to lipid peroxidation.     

Effects of 8-(2-dimethylaminoethyl)-3-oxo-4-phenyl-1-thia-4,8-diazaspiro [4,5] decane dihydrochloride monohydrate (Y-8845) on carbon tetrachloride-induced liver injury

The effects of 8-(2-dimethylaminoethyl)-3-oxo-4-phenyl-1-thia-4,8-diazaspiro [4, 5] decane dihydrochloride monohydrate (Y-8845) on carbon tetrachloride (CCl4)-induced liver injury were investigated in rats. CCl4-induced attenuation of the plasma cyclic AMP (cAMP) response to glucagon stimulation was significantly prevented by pretreatment with Y-8845. Y-8845 also effectively suppressed the increases in the activities of serum transaminases as well as the decreases in microsomal glucose-6-phosphatase activity and microsomal cytochrome P-450 concentrations induced by CCl4. In rats at 72 hr after CCl4 administration, the plasma cAMP response to glucagon, microsomal glucose-6-phosphatase activity and P-450 concentration were all below the control level. Y-8845 treatment after CCl4 administration rectified these reductions to nearly normal levels. Furthermore, Y-8845 stimulated DNA synthesis during liver regeneration after CCl4 intoxication. These results demonstrate that Y-8845 has a protective effect against CCl4-induced injury in the liver and a stimulating effect on the recovery of the damaged liver.     

The protective effects of (4R)-hexahydro-7,7-dimethyl-6-oxo-1,2,5-dithiazocine-4-carboxylic acid (SA3443), a novel cyclic disulfide, on chemically-induced acute liver injury

The effects of SA3443, a novel cyclic disulfide compound, on acute liver injuries induced by carbon tetrachloride (CCl4), D-galactosamine and DL-ethionine were studied in rats or mice. SA3443 (100-300 mg/kg, p.o.) significantly suppressed the increases of serum transaminase activity and liver triglyceride content in the CCl4 or DL-ethionine-induced model. Furthermore, SA3443 (300 mg/kg, p.o.) clearly reduced the formation of hepatic lipid peroxide in CCl4-treated rats. These results indicate that SA3443 protects the liver against acute liver injury.     

Effects of oxygen deficiency and calcium omission on carbon tetrachloride hepatotoxicity in isolated perfused livers from phenobarbital-pretreated rats

The effect of oxygen concentration and Ca2+ omission on CCl4-induced hepatotoxicity was studied in a non-recirculating and hemoglobin-free liver perfusion system using phenobarbital-pretreated rats. With 95% O2-saturated perfusate, infusion of 0.5 mM CCl4 caused an instantaneous increase of thiobarbituric acid reactive substances (TBA-RS) in the effluent perfusate, accompanied by only a slight leakage of K+ and lactate dehydrogenase (LDH). CBrCl3 produced a far greater increase in the TBA-RS level, but again with slight K+ and LDH leakage. With 20% O2-saturated perfusate, CCl4 caused a marked LDH leakage, which was preceded by an early and considerable increase in K+ leakage coupled with Na+ uptake, Ca2+ uptake was initially slight, being enhanced concurrently with the LDH leakage. The TBA-RS level changed biphasically with an initial moderate and a succeeding greater increase coupled with LDH leakage. N,N"-Diphenyl-p-phenylenediamine and promethazine suppressed the TBA-RS production, but improved neither K+ nor LDH leakage. Omission of the Ca2+ from the perfusate reduced the initial K+ leakage as well as the later TBA-RS release, and markedly delayed the LDH leakage. In retrograde perfusion under low oxygen supply with Ca2+, CCl4 produced essentially the same toxic manifestations as those observed in the anterograde perfusion. Hepatocytes of the periportal and pericentral areas were not stained with trypan blue in the antero- and retrograde perfusion systems respectively. Thus, oxygen deficiency, rather than lipid peroxidation by itself, and the essential role of extracellular Ca2+ may be important for CCl4-induced hepatic cell necrosis, in which plasma membrane permeability change may be an early and critical event.     

Lysosomal enzyme activity during development of carbon tetrachloride induced cirrhosis in rats

The present study was undertaken to determine whether there is any alteration in the activities of lysosomal enzymes in the liver and sera of rats during the course of carbon tetrachloride (CCl4) induced cirrhosis in rats. Cirrhosis was induced by the chronic administration of carbon tetrachloride plus phenobarbitone. N-acetyl glucosaminidase, P-glucuronidase and acid phosphatase were assayed spectrophotometrically in the liver homogenates and in the sera at different stages of liver injury i.e., necrosis, fibrosis, and cirrhosis. Significant increase in the "basal" activities of N acetyl glucosaminidase, beta-glucuronidase, and acid phosphatase were observed in the livers of rats during the course of development of cirrhosis. As the liver injury progressed from necrosis to cirrhosis, the 'free' activities of these three enzymes also increased. The 'total' activities of the enzymes studied were either decreased or remained unaltered. The increased 'free' activities of the lysosomal enzymes in the liver of CCl4 treated rats may contribute to cellular autophagy and tissue catabolism, which may subsequently lead to cirrhosis.     

Decrease in protein kinase and phosphatase activities in the liver nuclei of rats exposed to carbon tetrachloride.

The alteration in protein kinase and phosphatase activities in the liver nuclei of rats administered carbon tetrachloride (CCl(4)) was investigated. Rats received a single oral administration of CCl(4) (1 ml/100 g body wt of 5, 10, and 25% CCl(4) in corn oil), and 5, 24, and 48 h later they were euthanized by bleeding. The administration of CCl(4) (10 and 25%) caused a significant decrease in protein kinase activity in the liver nuclei. The enzyme activity in the liver nuclei from normal and CCl(4)-administered rats was significantly increased by the addition of Ca(2+) (0.5 mM) and calmodulin (10 microg/ml) in the reaction mixture, suggesting that Ca(2+)/calmodulin-dependent protein kinase activation is not suppressed by CCl(4) treatment. Liver nuclear phosphatase activity toward phosphotyrosine, but not phosphoserine and phosphothreonine, was markedly decreased by CCl(4) (5, 10, and 25%) administration. This decrease was seen 5 h after CCl(4) administration. The presence of vanadate (10(-4) M) in the reaction mixture caused a significant decrease in phosphotyrosine phosphatase activity in the liver nuclei from normal and CCl(4)-administered rats, whereas the enzyme activity was not decreased by okadaic acid (10(-5) M) or sodium fluoride (10(-3) M). The effect of anti-regucalcin antibody (100 ng/ml) in increasing phosphotyrosine phosphatase activity was seen in the liver nuclei of CCl(4)-administered rats, suggesting that regucalcin-sensitive phosphatase activity is decreased by CCl(4) administration. The present study demonstrates that CCl(4) administration induces a decrease in protein kinase and tyrosine phosphatase activities, which are involved in signaling factors in the liver nuclei of rats.