CCl4-injured Rats Research Articles

Catechin reduces liver inflammation by regulating Kupffer cell activation in rats

The liver is a defense against infections due to its strategic location between the gastrointestinal and systemic circulations. In dogs and cats, infectious hepatitis encompasses a range of contagious diseases affecting the liver either directly or as part of a broader systemic infection, including bacterial, mycobacterial, viral, fungal, protozoal, parasitic, and rickettsial diseases. Catechins possess well-recognized natural antioxidant properties. This study investigated their therapeutic potential for applications in hepatology, evaluating whether catechins reduce hepatic inflammation in rats repeatedly exposed to carbon tetrachloride (CCl4). Sprague-Dawley rats were given catechin 50 (C50) or 100 (C100) mg/kg body weight orally daily for 3 days. This treatment was given with or without concurrent intraperitoneal injections of CCl4. Phosphate-buffered saline served as the vehicle control, while silymarin administered at 100 mg/kg was used as the positive control.Gross examination revealed significant enlargement, edema, and darker tissue in CCl4-induced livers treated with vehicle. Additionally, spotty discoloration was observed on the surface. Kupffer cell activation suppressed the expression of inflammatory mediators, including inducible nitric oxide synthase (iNOS), in groups co-treated with catechin and CCl4; this effect was reversed when catalase replaced catechin in CCl4-injured rats. Catechin alleviates hepatic inflammation in rats repeatedly exposed to CCl4; it also modulates the activation of Kupffer cells and monocytes. These results should lead to new treatments for liver inflammation in veterinary practice.

Pulicaria crispa mitigates nephrotoxicity induced by carbon tetrachloride in rats via regulation oxidative, inflammatory, tubular and glomerular indices

Context Carbon tetrachloride (CCl4) induces oxidative stress in various tissues by altering antioxidants defense system. Recently, there has been a substantial use of phytotherapy to treat different diseases. Objective This study was designed to evaluate the curative effect of Pulicaria crispa (Forssk.) Benth et Hook (Family Asteraceae) aerial parts ethanol extract against CCl4 induced toxicity in rats kidneys. Materials and methods Nephrotoxicity was induced by intraperitoneal injection with CCl4 in a dose of 0.5 mL/kg b.wt./twice a week for six consecutive weeks. Serum kidney function tests, oxidative stress markers, inflammatory cytokines, nephrotoxicity biomarkers and histopathological observation were evaluated. Results CCl4 increased serum kidney function parameters, malondialdehyde level, inflammatory cytokines, and nephrotoxicity markers, while decreased certain oxidative stress indices as superoxide dismutase and glutathione refereeing to the control group (p < 0.0001). Administration of P. crispa ethanol extract to CCl4 injured rats attenuated these changes with variable degrees. The results were confirmed through the observed amelioration of the renal histological architectures. Conclusion P. crispa ethanol extract possesses potent curative effect against CCl4-induced nephropathy through improvement of kidney function, oxidative stress, inflammatory and nephrotoxicity index and the renal histopathological features. To establish the therapeutic and pharmacological applications of the plant, additional researches are required.

Hepatoprotective effect of Solanum surattense leaf extract against chemical- induced oxidative and apoptotic injury in rats

BackgroundOf over 35 Saudi plants traditionally used to treat liver disorders, majority still lack scientific validations. We therefore, evaluated the anti-oxidative, anti-apoptotic and hepatoprotective potential of Solanum surattense leaves total ethanol-extract (SSEE).MethodsThe cytoprotective (4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide/ MTT assay) and anti-apoptotic (caspase-3/7) potential of SSEE (25–200 μg/mL) were assessed in cultured HepG2 cells against dichlorofluorescein (DCFH)-induced toxicity. The hepatoprotective salutation of SSEE (100 and 200 mg/kg.bw/day) in carbon tetrachloride (CCl4)-intoxicated rats was evaluated by serum biochemistry and histopathology. The anti-oxidative activity of SSEE (31.25–500 μg/mL) was tested by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and linoleic acid bleaching assays. Also, SSEE was subjected to qualitative phytochemical analysis, and standardized by validated high-performance liquid chromatography (HPTLC).ResultsSSEE at doses 50, 100 and 200 μg/mL showed HepG2 cell proliferative and protective potential by about 61.0, 67.2 and 95%, respectively through inhibition of caspase-3/7 against DCFH-toxicity. In CCl4-injured rats, SSEE (200 mg/kg) significantly (P < 0.001) normalized serum transaminases, alkaline phosphatase, bilirubin, cholesterol, triglycerides, and total protein, including tissue malondialdehyde and nonprotein sulfhydryls levels, supported by the liver histopathology. SSEE further showed strong in vitro anti-oxidative and anti-lipid peroxidative activities, evidenced by the presence of alkaloids, flavonoids, tannins, sterols and saponins. Identification of β-sitosterol (3.46 μg/mg) strongly supported the anti-oxidative and hepatoprotective salutation of SSEE.ConclusionOur findings suggest the therapeutic potential of S. surattense against chemical-induced oxidative stress and liver damage. However, isolation of the active principles and elucidation of mechanism of action remain to be addressed.

The in vitro and in vivo anti-hepatotoxic, anti-hepatitis B virus and hepatic CYP450 modulating potential of Cyperus rotundus

In the present study we investigated the hepatotoprotective, hepatitis B virus (HBV) inhibitory and hepatic CYP450 enzyme (CYP3A4) modulatory potential of Cyperus rotundus rhizome fractions. The crude ethanol-extract, including different organic and aqueous fractions were tested for in vitro cytoprotection on HepG2 cells (MTT assay), followed by in vivo evaluation in Wistar rats (serum biochemistry and lipid profile). The in vitro anti-HBV activity was tested on HepG2.2.15 cells (HBsAg and HBeAg Elisa). Of these, the n-butanol and aqueous fractions showed the most promising, dose-dependent hepatoprotection in DCFH-injured HepG2 cells. Further, in CCl4-injured rats, oral administration of C. rotundus (100 and 200 mg/kg·bw/day) significantly normalized serum markers of healthy liver function (SGOT, SGPT, GGT, ALP and bilirubin) and lipid profile (cholesterol, HDL, LDL, VLDL, TG and MDA), including tissue NP-SH and TP levels. Compared to other fractions, the ethyl acetate, n-butanol and aqueous fractions exhibited the best inhibitory effects on viral HBsAg and HBeAg secretions in dose- and time-dependent manner. In addition, reporter gene assay (Dual-luciferase) of transfected HepG2 cells showed mild activation of nuclear PXR-mediated CYP3A4 gene by the three active fractions. Taken together, C. rotundus showed very promising hepatoprotective and anti-HBV potential in experimental settings. In addition, this is the first report on modulation of CYP3A4 by C. rotundus that suggests its safe consumption in relation to drug metabolism and efficacy. Our data could therefore, provide the basis for the ethnobotanical medicinal use of C. rotundus in metabolic liver disorder and hepatitis B patients.

Antioxidant and Hepatoprotective Effects of The Lipoidal Matters of Ficus Lutea Leaves

ABSTRACTThe antioxidant and hepatoprotective properties of the n-hexane fraction obtained by successive liquid fractionation of the crude cold ethanol extract (95%) of the dried powdered Ficus lutea leaves were evaluated by saponification and GC/MS analysis with column chromatography using silica gel. In vitro antioxidant effect was assessed by DPPH free radical technique and in vivo evaluation carried out on rats after carbon tetrachloride (CCl4) induction. The evaluation was done by determination of oxidative stress markers and liver function enzymes and examining histopathological picture of liver. Triterpenoidal and steroidal compounds lupenone (lupane skeleton): methyl isomasticadienonate (8-tirucallene skeleton), α-amyrin acetate, 20, 22- Epoxyeupha-24-ene-3-one, and stigmasterol were isolated and their structure elucidations were confirmed by spectral analysis MS, IR, and H1-NMR spectra. Treatment of CCl4-injured rats with plant extract showed amelioration in oxidative stress markers, liver function indices, and the hepatic architectures.

Therapeutic efficacy of ethanolic extract of Aerva javanica aerial parts in the amelioration of CCl4-induced hepatotoxicity and oxidative damage in rats

BackgroundLiver diseases, the fifth most common cause of global death, can be metabolic, toxin-induced, or infective. Though approximately 35 Saudi medicinal plants are traditionally used to treat liver disorders, the hepatoprotective potential of Aerva javanica has not been explored.ObjectiveTo investigate the antioxidative and hepatoprotective effect of Aerva javanica.DesignTotal ethanol extract of A. javanica aerial parts was prepared and tested on DCFH-toxicated HepG2 cells ex vivo, and in CCl4-injured Wistar rats in vivo. MTT assay was used to determine cell viability and the serum biochemical markers of liver injury as well as histopathology was performed. In vitro 1,1-diphenyl-2-picrylhydrazyl and β-carotene free-radical scavenging assay and phytochemical screening of the extract were done. Furthermore, A. javanica total extract was standardized and validated by high-performance thin layer chromatographic method.ResultsMTT assay showed that, while DCFH-injured cells were recovered to ~56.7% by 100 µg/ml of the extract, a 200 µg/ml dose resulted in hepatocytes recovery by ~90.2%. Oral administration of the extract (100 and 200 mg/kg.bw/day) significantly normalized the serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, gamma-glutamyl transferase, alkaline phosphatase, bilirubin, cholesterol, high-density lipoprotein, low-density lipoprotein, very-low-density lipoprotein, triglyceride, and malondialdehyde levels, including tissue nonprotein sulfhydryl and total protein in CCl4-injured rats. In addition, the histopathology of dissected liver also revealed that A. javanica cured the tissue lesion compared to silymarin treatment. In vitro assays revealed strong free-radical scavenging ability of the extract and presence of alkaloids, flavonoids, tannins, sterols, and saponins where rutin, a well-known antioxidant flavonoid, was identified.ConclusionsOur findings demonstrate the potential of A. javanica in the attenuation of ex vivo and in vivo hepatotoxicity and oxidative damage. This further suggests its therapeutic value in various liver diseases. However, isolations of the active principles, their mechanisms of action, and other therapeutic contributions remain to be addressed.

Hepatoprotective and antiviral efficacy of Acacia mellifera leaves fractions against hepatitis B virus.

The present study investigated the hepatoprotective and anti-HBV efficacy of Acacia mellifera (AM) leaves extracts. The crude ethanolic-extract, including organic and aqueous fractions, were tested for cytotoxicity on HepG2 and HepG2.2.15 cells (IC50 = 684 μg/mL). Of these, the ethyl acetate and aqueous fractions showed the most promising, dose-dependent hepatoprotection in DCFH-toxicated cells at 48 h. In CCl4-injured rats, oral administration of AM ethanol extract (250 and 500 mg/kg·bw) for three weeks significantly normalized the sera aminotransferases, alkaline phosphatase, bilirubin, cholesterol, triglycerides, and lipoprotein levels and elevated tissue nonprotein sulphydryl and total protein. The histopathology of dissected livers also revealed that AM cured the tissue lesions. The phytochemical screening of the fractions showed presence of alkaloids, flavonoids, tannins, sterols, and saponins. Further, anti-HBV potential of the fractions was evaluated on HepG2.2.15 cells. Of these, the n-butanol and aqueous fractions exhibited the best inhibitory effects on HBsAg and HBeAg expressions in dose- and time-dependent manner. Taken together, while the ethyl acetate and aqueous fractions exhibited the most promising antioxidant/hepatoprotective and anti-HBV activity, respectively, the n-butanol partition showed both activities. Therefore, the therapeutic potential of AM extracts warrants further isolation of the active principle(s) and its phytochemical as well as biological studies.

Danshensu-mediated protective effect against hepatic fibrosis induced by carbon tetrachloride in rats

The culprit of hepatic fibrosis (HF) is linked to suprathreshold deposition of collagen. Thus, collagen reduction by improved metabolism contributes to HF management. In this study, we aimed to investigate the hepatoprotective effects of Danshensu (DSS) against carbon tetrachloride (CCl4)-induced HF rats. The results showed that DSS-administrated rats resulted in decreasing in hepatosomatic indexes, and lowering serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Meanwhile, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) were increased, while the content of malonaldehyde (MDA) was lessened in liver tissue of DSS administration group. In addition, the pro-fibrotic markers of hydroxyproline (Hyp), type III procollagen (PCIII) and hyaluronic acid (HA) contents were decreased. Histopathological examination confirmed that the hepatotoxicity in CCl4-injured rats was alleviated following the DSS administration. Furthermore, intrahepatic protein expressions of alpha-smooth muscle actin (α-SMA), phosphorylated JAK2 (p-JAK2) and phosphorylated STAT3 (p-STAT3) were effectively down-regulated, respectively. Overall, this work demonstrates that DSS played the protective effect against CCl4-induced cytotoxicity in liver tissue, which the probable mechanism is associated with attenuation of lipid peroxidation, collagen accumulation and enhancement of anti-oxidative defense capability, as well as regulation of intrahepatic JAK/STAT pathway for maintaining collagenic homoeostasis.

Hepatoprotective effects of Lycium chinense Miller fruit and its constituent betaine in CCl4-induced hepatic damage in rats

The hepatoprotective activities of Lycium chinense Miller (LC) fruit extract and its component betaine were investigated under carbon tetrachloride (CCl4)-induced hepatotoxicity in rats. The treatment of LC fruit extract significantly suppressed the increase of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the sera of CCl4 injured rats, and restored the decreased levels of anti-oxidant enzymes such as total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and suppressed the expression of inflammatory mediators including inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-1 and -2. To visualize the potential activity of betaine, a component of LC fruit, betaine was substituted for LC extract in CCl4 injured rats. The biochemical profile in CCl4 injured rats co-treated with betaine matched those of LC fruit treated CCl4 injured rats. The ameliorative effects of LC extract, as well as betaine, were also confirmed by histopathological examination. Collectively, the present findings imply that LC fruit, via its component betaine, mitigate CCl4-induced hepatic injury by increasing antioxidative activity and decreasing inflammatory mediators including iNOS and COX-1/COX-2.

A comparative study on the tissue distributions of rhubarb anthraquinones in normal and CCl4-injured rats orally administered rhubarb extract

Aim of the studyThe present study comparatively investigated the tissue distributions of rhubarb anthraquinone derivatives (AQs) to examine whether they undergo different uptakes in normal or CCl4-induced liver-damaged rats, to explore possible reasons for the different toxicities of AQs in pathological model rats and normal rats at the tissue distribution level. Materials and methodsThe total rhubarb extract (14.49gkg−1 of body weight per day based on the quantity of crude material) was administrated orally to normal and model rats for 12 weeks. The concentrations of free AQs in tissues were quantitated by liquid chromatography–tandem mass spectrometry (LC–MS). After drug withdrawal for 4 weeks, tissue distributions were again determined. ResultsThe five free AQs—aloe-emodin, rhein, emodin, chrysophanol and physcion—were detected in the liver, kidney and spleen, while only rhein, aloe-emodin and emodin reached the quantitative limit. The tissue distributions of rhein (p<0.001), aloe-emodin (p<0.001) and emodin (p<0.05) in normal rats were higher than those in model rats with rhein>aloe-emodin>emodin in kidney and spleen tissues and aloe-emodin>rhein>emodin in liver tissues. Free AQs were not detected in the tissues after drug withdrawal for 4 weeks. ConclusionsThese results suggest that the tissue toxicity of AQs in normal animals is higher than that in pathological model animals with little accumulative toxicity of rhubarb. The results are concordant with the traditional Chinese theory of You Gu Wu Yun recorded first in Su Wen, a classical Chinese medical treatise.

Zizyphusspina-christi protects against carbon tetrachloride-induced liver fibrosis in rats

The study of chronic hepatic fibrosis has been receiving an escalating attention in the past two decades. The aim of the study was to examine the effects of the water extract of Zizyphus spina-christi (L.) (ZSC) on carbon tetrachloride (CCl 4)-induced hepatic fibrosis. ZSC extract was daily administered [alone (ZSC-control group) or along with CCl 4 (protected groups)] at 0.125 (low dose), 0.250 (medium dose) and 0.350 (high dose) g/kg b.wt. for 8 weeks. Histo-pathological, biochemical and histology texture analyses revealed that ZSC significantly impede the progression of hepatic fibrosis. ZSC resulted in a significant amelioration of liver injury judged by the reduced activities of serum ALT and AST. Oral administration of ZSC has also restored normal levels of malondialdehyde and retained control activities of endogenous antioxidants such as SOD, CAT and GSH. Furthermore, ZSC reduced the expression of α-smooth muscle actin, the deposition of types I and III collagen in CCl 4-injured rats. Texture analysis of microscopic images along with fibrosis index calculation showed improvement in the quality of type I collagen distribution and its quantity after administration of ZSC extract. These results demonstrate that administration of ZSC may be useful in the treatment and prevention of hepatic fibrosis.

Overexpression of the gene for transmembrane 4 superfamily member 4 accelerates liver damage in rats treated with CCl 4

Transmembrane 4 superfamily member 4 (TM4SF4) is up-regulated in regenerating liver after partial hepatectomy in rats, but the in vivo functions of this protein are still largely unknown. Therefore, we investigated the role of TM4SF4 during liver injury. Expression of TM4SF4 was analyzed by RT-PCR and Western blotting in normal and CCl4-injured rats. Overexpression or reduced expression of TM4SF4 in the liver was achieved by injection of sense or antisense TM4SF4 expression plasmids. Assessment of liver injury (histology, serum ALT and AST levels), apoptosis by TUNEL assay were performed. Expression of injury-related genes was analyzed by quantitative real-time PCR. Overexpression of TM4SF4 in rats after CCl4 treatment showed extensive liver damage and increased levels of serum ALT and AST. Decreased TM4SF4 gene expression showed minimal liver necrosis and depressed ALT and AST levels. Increased expression of TM4SF4 affected the expression levels of growth factors and receptors, such as TNF-alpha, TNFR1 and c-met. Furthermore, pro-apoptotic and anti-apoptotic gene expression was altered after TM4SF4 administration. Rat TM4SF4 is overexpressed in acutely injured liver induced by CCl4 and plays a crucial role in accelerating liver injury, which may be mediated by the TNF-alpha and HGF/c-met signaling pathways.

Therapeutic effect of transplanting HGF-treated bone marrow mesenchymal cells into CCl 4-injured rats

The autologous transplantation of bone marrow cells is a promising treatment for liver disease. Pluripotent bone marrow stem cells can differentiate into hepatocytes, but few reports address the therapeutic effect of transplanting these stem cells into damaged liver in vivo. Here, we transplanted bone marrow-derived mesenchymal cells (BMMCs) to test their effect in liver-injured rats. Rat bone marrow cells were cultivated for 2 weeks in the presence or absence of hepatocyte growth factor (HGF), labeled with a fluorescent marker, and transplanted by injection into CCl(4)-injured rats. Blood samples collected 4 weeks later were analyzed for albumin production and transaminase levels. The amount of fibrosis was determined by histology. RT-PCR analysis detected alpha-fetoprotein and albumin mRNAs in BMMCs cultured with HGF for 2 weeks. Albumin protein was also produced in the BMMC cultures by a subpopulation of cells. Transplantation of the BMMCs into liver-injured rats restored their serum albumin level and significantly suppressed transaminase activity and liver fibrosis. These effects were not seen when the BMMCs were cultured without HGF. The transplantation of BMMCs cultured with HGF effectively treats liver injury in rats. This is a promising technique for autologous transplantation in humans with liver injury.

Effects of oxymatrine on experimental hepatic fibrosis and its mechanismin vivo

Hepatic fibrogenesis has close relation with hepatic stellate cells (HSC) and tissue inhibitors of metalloproteinase (TIMP). Oxymatrine (OM) is a kind of Chinese herb that is found to have some effects on liver fibrosis. We aimed to determine the effects of OM on hepatic fibrosis and explore the possible mechanism. Thirty-two rats were randomly divided into four groups; 16 were used to develop hepatic fibrosis by carbon tetrachloride (CCl4) and treated with or without OM, and 16 were used as controls. The expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and alpha-smooth muscle actin (alpha-SMA) in the livers of rats was detected by immunohistochemical assay. Liver pathology was determined by H and E staining and reticulum staining. In CCl4-injured rats, the normal structure of lobules was destroyed, and pseudolobules were formed. Hyperplasia of fibers was observed surrounding the lobules. While the degree of fibrogenesis in liver tissues was significantly decreased in those rats with OM-treatment compared with those without OM treatment. The pseudolobules were surrounded by strong, multi-layer reticular fibers, which netted into pseudolobules in CCl4-injured rats, however, there was a significant decrease in reticular fibers in OM-treated rats. The expression of TIMP-1 in hepatic cells was weak in control groups, but strong in CCl4-injured groups, however, the expression of TIMP-1 was significantly inhibited by OM (F = 52.93, P<0.05). There was no significant change in the expression of alpha-SMA between CCl4-injured rats with or without OM treatment (F = 8.99, P>0.05). OM effectively inhibits CCl4-induced fibrogenesis in rat liver tissues, probably by reducing the expression level of TIMP-1.

The active metabolite of leflunomide A771726 inhibits proliferation and collagen synthesis of hepatic stellate cell

To investigate the effect of the metabolite of leflunomide, A771726,on proliferation and collagen synthesis of hepatic stellate cell (HSC). HSC and Kupffer cells were isolated from the rat liver by collagenase IV and pronase perfusion, and purified by density gradient separation. The effects of A771726 on cell proliferation and collagen synthesis were examined by 3H-thymidine and 3H-proline incorporation assays, respectively. The TGF-beta, TNF-alpha and IL-1 levels in Kupffer cell conditioned medium (KCCM) were determined by enzyme-linked immunosorbent assay (ELISA). HSC and Kupffer cells in rat liver were well separated. The KCCM of CCl4-injured rats had significant stimulation effect on proliferation and collagen synthesis of HSC in primary culture. Addition of A771726 (0.001-10 micromol/Lein HSC culture stimulated by KCCM significantly inhibited proliferation and collagen synthesis of HSC. Furthermore, the elevated TGF-beta, TNF-alpha and IL-1 levels in KCCM of CCl4-injured rats were significantly reduced in A771726 treatment groups. A771726 has markedly inhibitory effect on proliferation and collagen synthesis of HSC and secretion of TGF-beta,TNF-alpha and IL-1 from Kupffer cells.

S-Adenosylmethionine prevents hepatic tocopherol depletion in carbon tetrachloride-injured rats

In various experimental models, S-adenosylmethionine (SAMe) has been shown to reduce liver injury by preventing depletion of glutathione, one of the antioxidant systems that plays a critical role in defence against oxidative stress. On the other hand, alpha-tocopherol may be decreased in liver diseases, and treatment with this vitamin reduces liver injury in CCl(4)-treated rats. Since there is a close relationship among the different antioxidant systems (mainly glutathione, alpha-tocopherol and ascorbic acid), we have assessed whether, as well as restoring hepatic glutathione content, SAMe has any effect on liver alpha-tocopherol and ascorbic acid levels in CCl(4)-injured rats. Four groups of seven male Wistar rats treated for 9 weeks were studied: rats induced to cirrhosis with CCl(4), rats induced to cirrhosis plus SAMe administration (10 mg x kg(-1) x day(-1)) and their respective controls. Liver samples were obtained for measuring levels of glutathione, alpha-tocopherol, ascorbic acid and thiobarbituric acid-reactive substances (TBARS), and hydroxyproline concentration as an index of collagen content. The hydroxyproline content was higher in CCl(4)-injured rats than in the control group (4.4+/-1.8 and 1.1+/-0.3 micromol/g respectively; P<0.05). In CCl(4)-injured rats, SAMe administration decreased collagen content (2.7+/-1.0 microl/g; P<0.05) and TBARS, and corrected glutathione depletion. alpha-Tocopherol was significantly lower in CCl(4)-injured rats than in controls (17.3+/-4.9 and 23.0+/-4.0 micromol/g respectively; P<0.05). By contrast, alpha-tocopherol levels were similar (23.8+/-5.1 micromol/g) in CCl(4)-injured rats receiving SAMe and in controls. In CCl(4)-injured rats, liver ascorbic acid was decreased in comparison with controls (4.9+/-1.8 and 8.2+/-1.0 micromol/g respectively; P<0.05), levels which were not replenished by SAMe (4.6+/-0.4 micromol/g). In conclusion, SAMe not only decreases fibrosis and protects against hepatic glutathione depletion, but has a further antioxidant effect of preventing alpha-tocopherol depletion in CCl(4)-injured rats.

Brain tyrosine hydroxylase activity and calculated amount of brain dopa synthesized in carbon tetrachloride-intoxicated rats.

Tyrosine hydroxylase activity in the corpus striatum was measured in a large dose of carbon tetrachloride (CC14)-intoxicated rats in order to confirm whether brain catecholamine contents decrease in acute hepatic failure or not. Theoretical amounts of dopa synthesized in the brain of the treated animals were calculated according to an equation of enzyme kinetics. Tyrosine hydroxylase activities in CCl4-injured rats were similar to those in control rats, and calculated amounts of brain dopa in liver-injured rats were rather higher as compared to those in untreated animals.

Effects of liver injury and cholestasis on microsomal enzyme activities and metabolism of halothane, enflurane and methoxyflurane in vivo in rats.

1. Cholestasis (bile-duct ligation 24 h before) had no effect on rat liver microsomal protein content, cytochrome P-450 or cytochrome c reductase activity, but depressed aniline hydroxylase activity and aminopyrine demethylase less so. Pretreatment with CCl4 (24 h before) decreased rat liver cytochrome P-450, aniline hydroxylase and aminopyrine demethylase. 2. Halothane, enflurane and methoxyflurane are metabolized via different pathways, resulting in different metabolic elimination rates in our exposure system (methoxyflurane greater than halothane greater than enflurane). Elimination half-lives of the three compounds from the atmosphere of the exposure system were three times longer in CCl4-injured rats; cholestasis had a weaker effect (30-50% increase). 3. Dehalogenation of enflurane, which is the preferred pathway, is affected to the same extent as the cytochrome P-450-dependent hydroxylation of halothane and the O-dealkylation of methoxyflurane.

QUANTITATIVE ENZYME HISTOCHEMISTRY OF NORMAL AND INJURED LIVERS

G6PD and ICD activity within the hepatic lobule was determined quantitatively by the ultramicrochemical method of Lowry in CCl4-injured liver of rats and their controls. The activity of G6PD, ICD and NADPH diaphorase was evaluated simultaneously by two histochemical staining methods: the Meijer method using phenadine methosulfate (PMS) and menadione as intermediate electron acceptors and the Pearse method without using PMS or menadione. By the ultramicrochemical method, the G6PD activity increased remarkably and ICD activity decreased in the central area which was most severely affected in CCl4-injured rats. By the Pearse method, the activities of these three enzyme decreased or diminished in the central area. The Meijer method, however, demonstrated considerable G6PD and ICD activity in the central area. Further examination confirmed that such discrepancies were related to NADPH diaphorase which is generally considered the rate-limiting factor in the staining of NADP-linked dehydrogenases. Increased G6PD activity and considerable ICD activity were detected even in necrotic cells by the ultramicrochemical method and the Meijer method.