Decrease in the number of receptors for epidermal growth factor in the liver of D-galactosamine-intoxicated rats.

Hepatic transport of epidermal growth factor (EGF) was studied in D-galactosamine-intoxicated rats by the multiple-indicator dilution (MID) method. The extraction ratio of 125I-labeled EGF in the intoxicated rats, obtained from a model-independent analysis of the dilution curves, decreased to 45% of the control values. A distributed two-compartment model was fitted to the dilution data by nonlinear least-squares regression, and the kinetic parameters, kon.PT (product of on-rate constant and receptor density), koff (off-rate constant) and ks (sequestration rate constant) were determined. The values of kon.PT and ks in the intoxicated rats decreased to approximately one-half and one-third of those in the control rats respectively. Similar decreases in the kon.PT and ks values in the intoxicated rats were also observed for the transport of 125I-labeled insulin, a positive control, into the liver. The 125I-labeled EGF binding experiment at equilibrium using liver homogenates revealed that the intoxication reduced the receptor density (PT) to one-third of the control values, whereas the equilibrium dissociation constant (kd) did not change significantly. The activities of Na+,K+-ATPase, cytochrome P-450 and glutathione S-transferase decreased in the intoxicated rats to 70-80% of the control values. The number of nuclei per unit area of tissue slices was also reduced to 70% of the control. Thus, the extent to which the enzyme activities and the number of nuclei decreased in the intoxicated liver was smaller than that of the number of EGF receptors. It is concluded that the reduction of EGF receptors cannot be explained by the "intact hepatocyte hypothesis" but rather by the functional change of hepatocytes induced by the administration of D-galactosamine.

Protective effect of (+)cyanidanol-3 in acute liver injury induced by galactosamine or carbon tetrachloride in the rat.

Pretreatment of rats with (+)cyanidanol--3 decreases the alterations in liver function tests (transaminase and bilirubin) as well as the accumulation of hepatic triglycerides induced by acute doses of galactosamine or carbon tetrachloride. This action was related to the dose of (+)cyanidanol-3 administered. The lowest effective doses were 3 intraperitoneal injections of 125 mg/kg administered before galactosamine or carbon tetrachloride. In the case of carbon tetrachloride intoxication, in vivo administration of (+)cyanidanol-3 reduced to a slight extent the absorption of conjugated dienes produced in liver microsomal lipid. This observation confirms that (+)cyanidanol-3 is able to prevent lipid peroxidation in vivo. As the protective effect of (+)cyanidanol-3 becomes apparent in two types of intoxication which are very different in their primary mechanisms of action, it is suggested that, the flavonoid also acts on a later stage of the process leading to necrosis and steatosis of the liver.

Treatment of chronic liver injury in mice by oral administration of xiao-chai-hu-tang.

Oral administration of Xiao-Chai-Hu-Tang, the extract of a mixture of seven herbs, attenuated the hepatic fibrosis developed in mice after repeated doses of carbon tetrachloride. Its pre-administration reduced the derangement of liver function tests seen after a single dose of carbon tetrachloride as well as that seen after d-galactosamine intoxication. Xiao-Chai-Hu-Tang may be effective in the treatment of chronic liver injury through hepatocytoprotection.

Studies of liver phosphorylase in hepatic injuries. I. Alteration in enzyme activity.

Phosphorylase activities (total and a form) were determined in the livers of experimental hepatic injuries with carbon tetrachloride or galactosamine and the livers of patients with liver diseases. Experimental liver injuries caused a slight decrease in total activity in later stages and a marked increase in a form activity in earlier stages. In human livers, low values of total activity were found in acute hepatitis and cirrhosis of the liver with no consistent alteration in a activity. Phosphorylase activities in hepatocellular carcinomas were also low. The importance of the altered phosphorylase activities in hepatic injuries is discussed in relation to the disorder in glycogen metabolism in the injured liver.

Effect of 4-phenyl-1,3-dithia-2-thioxo-cyclopent-4-ene on liver injury induced by repeated exposure to galactosamine plus carbon tetrachloride in rats.

The protective effects of 1,3-dithia-2-thioxo-cyclopent-4-ene (DT827A),4-phenyl-1,3-dithia-2-thioxo-cyclopent- 4-ene (DT827B) and 4-(4-fluorophenyl)-1,3-dithia-2-thioxo-cyclopent-4-ene (DT827C) on liver injury induced by D-galactosamine plus carbon tetrachloride (D-GalN + CCl4) and that of DT827B on liver injury induced by thioacetamide were studied using male rats. Out of the three DT827 series of compounds, DT827B was more effective on liver injury induced by the combination exposure to D-GalN + CCl4 for 4 weeks, and accordingly the following two experiments were carried out using DT827B only. Twelve-week administration of DT827B at dose levels of 5, 10 and 20 mg/kg/day revealed a therapeutic effect against liver injury induced by D-GalN + CCl4 dose-dependently, and another twelve-week administration of DT827B at the same three dose levels also revealed a therapeutic effect against liver injury induced by thioacetamide dose-dependently. A hepatoprotective potential of DT827B was suggested under the conditions of these studies.

Ameliorative effect of an urinary preparation on acetaminophen and D-galactosamine induced hepatotoxicity in rats.

The effect of oral administration of a preparation of human urine (PHU) on acute liver injury was examined in rats intoxicated with acetaminophen and D-galactosamine. The results indicated that PHU protected the liver from acetaminophen and D-galactosamine-induced injury as judged by morphological and biochemical observation. An increase in lipid peroxide concentrations and decrease in protein concentrations occurred in the liver by D-galactosamine injection, PHU administration significantly prevented these changes.

[Lidocaine as an immunomodulator in a toxic liver lesion]. / Lidokain kak immunomoduliator pri toksicheskom porazhenii pecheni.

D-galactosamine (DGA) increases the malonic dialdehyde (MDA) content in the erythrocytes, reduces the ATP content, and induces the appearance of immunosuppressive properties in the red cells. Administration of lidocaine attenuates or completely removes these effects of DGA in poisoned animals. Extracorporeal treatment of the erythrocytes of intact rats with blood serum of DGA-poisoned reduces the ATP content and induces the appearance of immunosuppressive properties in the erythrocytes. Blood serum of DGA-poisoned rats which had been given lidocaine does not cause such effects.

[The effect of Essentiale and riboxin on the immunomodulating properties of the erythrocytes in a toxic liver lesion]. / Vliianie éssentsiale i riboksina na immunomoduliruiushchie svoistva éritrotsitov pri toksicheskom porazhenii pecheni.

D-galactosamine (DGA) increases the erythrocyte content of malonic dialdehyde (MDA) and the degree of peroxide hemolysis (DPH) of the erythrocytes, and reduces the 2,3-diphosphoglycerate (DPG) and ATP content. DGA induces the appearance of immunosuppressive properties in light erythrocytes. Essentiale (2 mg/kg) reduces the MDA content and DPH in the heavy erythrocytes and induces the appearance of immunostimulating properties in them. Riboxine (2 mg/kg) reduces the content of DPG and ATP in the light erythrocytes and prevents the appearance of immunosuppressive properties in them. Injection of 2 mg/kg of Essentiale or riboxine does not affect the development of the immune response induced by sheep erythrocytes in DGA poisoned rats. Combined injection of the compounds in a dose of 1 mg/kg intensifies the immune response of the poisoned animals.

[The antitoxic function of the liver in D-galactosamine poisoning]. / Antitoksicheskaia funktsiia pecheni pri intoksikatsii D-galaktozaminom.

Two intragastric administrations of 500 mg/kg of D-galactosamine reduce the RNA and the cytochrome P-45, and b5 content in the hepatic microsomes of rats; inhibit the activity of aminopyrine-N-demethylase, hexobarbital hydroxylase, aniline-p-hydroxylase, and glutathione-S-transferase; reduce the rate of NADP.H and NAD.H oxidation; accelerate inactivation of cytochrome P-450 to cytochrome P-420; reduce the number of points of hexobarbital binding with N-octilamine, though increase the hemoprotein affinity to these substrates. Destruction of the nucleus, endoplasmic reticulum, and mitochondria occurs in the hepatocytes of D-galactosamine poisoned rats.

Induction of Nrf2 and metallothionein as a common mechanism of hepatoprotective medicinal herbs.

Many Chinese medicines have the potential to be hepatoprotective and therefore can be used to treat acute and chronic liver diseases. The challenge is to identify the molecular target for their protective mechanism. This study investigated the induction of nuclear factor-erythroid 2(NF-E2)-related factor 2 (Nrf2) antioxidant genes and metallothionein as a common mechanism of hepatoprotective effects of Chinese medicines such as Piper puberulum. Mice were pretreated with Piper puberulum extract (PPE, 500 mg/kg, po) or vehicles for seven days, followed by intoxication with CCl 4 (25 µl/kg, ip for 16 h), D-galactosamine (800 mg/kg, ip for 8 h), or acetaminophen (400 mg/kg, ip for 8 h). Hepatotoprotection was evaluated by serum enzyme activities and histopathology. To determine the mechanism of protection, mice were given PPE (250-1000 mg/kg, po for seven days) and livers were collected to quantify the expression of Nrf2-targeted genes and metallothionein. Nrf2-null mice were also used to determine the role of Nrf2 in PPE-mediated hepatoprotection.PPE pretreatment protected against the hepatotoxicity produced by CCl 4, D-galactosamine, and acetaminophen, as evidenced by decreased serum enzyme activities and ameliorated liver lesions. PPE treatment increased the expression of hepatic Nrf2, NAD(P)H:quinone oxidoreductase1 (Nqo1), heme oxygenase-1 (Ho-1), glutamate-cysteine ligases (Gclc), and metallothionein (MT), at both transcripts and protein levels. PPE protected wild-type mice from CCl 4 and acetaminophen hepatotoxicity, but not Nrf2-null mice, fortifying the Nrf2-dependent protection. In conclusion, induction of the Nrf2 antioxidant pathways and metallothionein appears to be a common mechanism for hepatoprotective herbs such as PPE.

Activation of mitogen activated protein kinase (MAPK) during D-galactosamine intoxication in the rat liver.

A significant increase in plasma glutamate-oxaloacetate transaminase and glutamate-pyruvate transaminase was observed 6 h after intraperitoneal administration of D-galactosamine (D-Galn). Three hours after administration of D-Galn, the vitamin C concentration in the liver decreased significantly compared to that in a control group and thereafter the hepatic vitamin C concentration remained at a significantly lower level. Phosphorylated JNK (c-Jun NH2-terminal kinase) and phosphorylated ERK (extracellular signal-regulated kinase) started increasing 3 h after D-Galn treatment and remained at a high level for 6-12 h after the treatment, while phosphorylated p38 MAPK increased significantly 6 h after D-Galn administration. These results indicated that oxidative stress and the activation of JNK and ERK took place almost simultaneously, followed by the activation of p38 MAPK.

Factors effective in reducing rat mortality due to acute liver failure as induced by D-galactosamine poisoning.

Mortality from D-galactosamine hydrochloride (D-GalN)-induced acute liver failure (ALF) in rats can be reduced by (1) transplanting intact hepatocytes; (2) injecting cytosol from fractionated hepatocytes dispersed from a liver subjected to 70% hepatectomy 24 hr earlier (CYT-H); (3) injecting a cell-free supernate derived from cultured hepatocytes (SUP); or (4) injecting neuraminidase-treated plasma where the plasma is drawn 24 hr after donor rats are subjected to 70% hepatectomy (PHP-neu). These treatments are effective when administered 20-24 hr after D-GalN poisoning, but experiments to determine the alterations in mortality rates as a function of time of treatment in relation to poisoning have not been performed. Two experiments are reported here. In the first the survival of lethally poisoned rats was compared after intravenously injecting either SUP prepared from cultured hepatocytes of syngeneic adult or fetal rat sources, or CYT-H from syngeneic adult rats 20 hr after poisoning. Untreated rats, rats treated with culture media alone, or rats treated with CYT from a nonregenerating source had an 88-100% mortality, with all deaths occurring within 72 hr following poisoning. Improved survival followed all other treatments: 55% of the rats receiving adult SUP, 70% of the rats receiving fetal SUP, and 80% of the rats receiving CYT-H survived. In the second experiment the survival of poisoned rats was compared after injecting them with PHP-neu, PHP not treated with neuraminidase (PHP without neu), and neuraminidase-treated plasma from sham-operated rats (SP-neu) or normal, nonoperated rats (NP-neu) 20 hr after poisoning.(ABSTRACT TRUNCATED AT 250 WORDS)

[Morphological changes in the liver in acute galactosamine poisoning with different protein levels in the diet]. / Morfologicheskoe izmenenie pecheni pri ostrom otravlenii galaktozaminom pri razlichnom soderzhanii belka v pishche.

Changes in hepatocyte ultrastructure after galactosamine administration to rats adapted to diets with different protein content have been studied. Typical galactosamine effects on hepatocytes were manifested earlier in animals on low and high protein diets. At the same time a considerable decrease in protein synthesis led to insufficient expression of the reparative processes in all the observed groups of animals.

Hepatic cysteamine and non-protein sulfhydryl levels following cystamine or cysteamine treatment of galactosamine-poisoned rats.

Hepatic cysteamine and non-protein sulfhydryl (NPSH) levels were determined in galactosamine (GAL)-poisoned rats following hepatoprotective cystamine or cysteamine treatments to determine whether alterations of hepatic NPSH status could contribute to their observed protective actions. D(+)-Galactosamine HC1 (400 mg/kg, ip) was administered to male Sprague-Dawley rats at 8 pm. Cystamine diHC1 (300 mg/kg, po) or cysteamine HC1 (170 mg/kg, ip) were administered 12 hr after GAL. Hepatic NPSH levels were determined using Ellman's reagent. Hepatic cysteamine levels were determined by separating NPSH Ellman's derivatives by reversed phase HPLC. Cystamine and cysteamine caused transient elevation of NPSH levels of 1-2 nanomoles/mg liver which correlated with the presence of 1-2 nanomoles of cysteamine/mg liver. However, neither cystamine nor cysteamine prevented NPSH levels from falling to 3 nanomoles/mg tissue 24 hr after GAL. Hepatoprotective treatments did not affect long term NPSH status in GAL-poisoned rats. However, transient NPSH increases, due to the intrahepatic presence of cysteamine, may contribute to the therapeutic effects of these hepatoprotective agents.

Bioartificial liver using hepatocytes on biosilon microcarriers: treatment of chemically induced acute hepatic failure in rats.

An artificial liver support procedure based on hemoperfusion via hepatocytes cultured on microcarriers is described. The efficiency of the system was assessed by the survival rate of rats treated with either lethal dosage of 7% CCl4 [30 ml/kg body weight (b.w.)] or D-galactosamine (2.5 g/kg b.w.). In CCl4-treated rats, hemoperfusion via empty microcarriers (n = 16) revealed no surviving animals, whereas the use of the bioartificial liver (n = 11) resulted in 80% (p less than 0.01) and 60% (p less than 0.05) survival 48 and 168 h after hepatotoxin, respectively. For the same time periods, the survival rate in D-galactosamine-intoxicated rats after hemoperfusion with hepatocytes (n = 20) was approximately 60% (p less than 0.05) and was only 5% in those of rats treated with empty microcarriers (n = 20). Sublethal dosage of 7% CCl4 (15 ml/kg b.w.) caused 25% mortality and prolonged (48 h) increase of activity of the liver enzymes and bilirubin levels in the serum of surviving animals. In these rats (n = 8) at the end of 3 h of hemoperfusion via hepatocytes, the bilirubin concentration decreased by 45% as compared with the control group (n = 6) treated with empty microcarriers. Moreover, by 48 h after intoxication, the use of the bioartificial liver resulted in more than a three-fold decrease in glutamate-oxaloacetate transaminase and a 10-fold decrease in glutamate-pyruvate transaminase serum activity as well as a fivefold decline in total and a ninefold decline in conjugated bilirubin levels as compared with the control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

[The correction with hepatic protectors of structural metabolic disorders in the liver in D-galactosamine poisoning]. / Korrektsiia gepatoprotektorami strukturno-metabolicheskikh narushenii v pecheni pri intoksikatsii D-galaktozaminom.

The hepatoprotective agents silybinin, essentiale and eplir (the complex of phospholipids and caratinoids from the mud) prevent in D-galactosamine-induced intoxication of rats the development of hepatitis, hepatocyte necrosis, a decrease in hepatocytes of the activity of the enzymes of mitochondria and endoplasmic reticulum, labilization of lysosomes. These drugs stimulate D-galactosamine-suppressed antitoxic function of the liver: they increase the contents of RNA, cytochromes P-450, b5, the activity of amidopyrine-D-demethylase, hydroxylases of hexobarbital and aniline, improve the activity of the respiratory chain of microsomes, counteract inactivation of cytochrome P-450 into cytochrome P-420. Essentiale and eplir activate conjugation of xenobiotics with reduced glutathione.