Development Of Hepatic Necrosis Research Articles

The dopamine agonist piribedil exerts hepatoprotective effects on carbon tetrachloride-induced hepatic damage

This study aimed to investigate the effect of piribedil, a drug used for the treatment of Parkinson’s disease and which has direct dopaminergic stimulating action, on the acute hepatic injury in mice. Hepatotoxicity was induced by CCl4 orally (0.28 ml/kg). Piribedil at three dose levels (4.5, 9, or 18 mg/kg) or silymarin (25 mg/kg) was given orally daily for 7 days, starting at time of administration of CCl4. Liver damage was assessed by determining liver serum enzyme activities and by hepatic histopathology. Piribedil administration lessened the increases in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) and also prevented the development of hepatic necrosis caused by CCl4. The effect of piribedil was dose-dependent one. Piribedil administered at the above doses caused significant reduction in the elevated plasma ALT by −36.3%, −42.8%, and −52.4% and ALP by −25%, −36.9%, and −57.1%, respectively. AST decreased by −36.4% and −46.2% by piribedil at 9 or 18 mg/kg, respectively. In comparison, the elevated serum ALT, AST, and ALP levels decreased to −69.6%, −64.2%, and −68.5% of control values, respectively, by silymarin. Histopathologic examination of the livers of CCl4-treated mice administered piribedil at 9 mg/kg showed noticeable amelioration of the liver tissue damage, while piribedil at 18 mg/kg resulted in restoration of the normal architecture of the liver tissue as well as noticeable increase in the protein content of hepatocytes. It is concluded that administration of the dopaminergic agonist piribedil in a model of liver injury induced by CCl4 results in amelioration of liver damage.

Histopathology of adult Pacific herring in Prince William Sound, Alaska, after the Exxon Valdez oil spill

Pacific herring (Clupea pallasi) sampled from oiled sites in Prince William Sound, Alaska, U.S.A., 3 weeks after the 1989 Exxon Valdez oil spill had multifocal hepatic necrosis and significantly increased tissue concentrations of polynuclear aromatic hydrocarbons (PAH). By comparison, Pacific herring from reference sites in 1989 and from all sites in 1990 and 1991 did not have hepatic necrosis or increased PAH concentrations. Adult Pacific herring were sampled for histopathology of liver, spleen, and kidney from oiled and reference sites in April (1989 and 1991) and October (1990 and 1991). Increased scores for macrophage aggregates contributed to significant differences in 1990, but these differences probably resulted from sampling older fish from the oiled site. Naphthalenes were the predominant PAH in all tissue samples. The development of hepatic necrosis and the predominance of naphthalenes in samples from 1989 is consistent with recent laboratory study in which crude oil exposure resulted in dose-dependent expression of viral hemorrhagic septicemia virus (VHSV). We conclude that Pacific herring were exposed to Exxon Valdez oil in 1989 and that development of hepatic necrosis in exposed fish probably was a result of VHSV expression.

Ultrastructural study of development of hepatic necrosis induced by TNF-alpha and D-galactosamine.

Recent studies have suggested an association between tumor necrosis factor-alpha (TNF-alpha) and the development and progression of acute liver failure. To investigate the role of TNF-alpha in the mechanism of massive hepatic necrosis, we studied a mouse model of TNF-alpha and D-galactosamine (GalN) -induced hepatic necrosis by ultrastructural analysis. Administration of GalN caused edema of hepatocellular microvilli and widening of sinusoidal endothelial fenestrae (SEF); administration of TNF-alpha caused only a widening of the SEF. Massive hepatic necrosis with hemorrhage was seen 6 hr after concomitant administration of TNF-alpha and GalN. In the ultrastructural analysis, edema of the hepatocellular microvilli, widening of the SEF, and transmigration of red blood cells (RBC) and platelets to the space of Disse without exfoliation and necrosis of the sinusoidal endothelial cells were observed. Fibrin deposits were seen in areas adjacent to injured hepatocytes. The diameter of the SEF was significantly greater than in the nontreated group and the groups treated with TNF-alpha or GalN alone. These results suggest that as a consequence of the increase in diameter of the SEF, transmigration of RBCs and platelets to the space of Disse may have resulted in massive hepatic necrosis due to occlusion of the microcirculation.

Role of adhesion molecules in the development of massive hepatic necrosis in rats

Massive hepatic necrosis develops after endotoxin administration in rats pretreated with heat-killed Propionibacterium acnes as a result of microcirculatory disturbance caused by endothelial cell destruction by activated macrophages in the hepatic sinusoids. Immunohistochemical hepatic expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen 1 α (LFA-1 α) and the effect of monoclonal antibodies against both adhesion molecules on liver necrosis provoked after endotoxin administration was studied in these rats. There were increased stains of ICAM-1 in endothelial cells and LFA-1 α in macrophages in the hepatic sinusoids in Propionibacterium acnes-pretreated rats compared with normal rats. Such stains were further increased soon after endotoxin administration, followed by development of hepatic necrosis. Monoclonal antibodies against both adhesion molecules significantly attenuated the extent of liver injury compared with controls, without affecting the infiltration and activation of hepatic macrophages. Polyclonal antibodies against polymorphonuclear leukocytes eradicated circulating neutrophils, but did not change such liver injury, although gum arabic, which suppressed macrophage activation, attenuated the extent of liver injury. Thus, adhesion between endothelial cells and activated macrophages in the hepatic sinusoids via ICAM-1 and LFA-1 α is essential for the initiation of massive hepatic necrosis of this type. Contribution of neutrophils seems less likely.

Role of adhesion molecules in the development of massive hepatic necrosis in rats

Massive hepatic necrosis develops after endotoxin administration in rats pretreated with heat-killed Propionibacterium acnes as a result of microcirculatory disturbance caused by endothelial cell destruction by activated macrophages in the hepatic sinusoids. Immunohistochemical hepatic expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen 1 alpha (LFA-1 alpha) and the effect of monoclonal antibodies against both adhesion molecules on liver necrosis provoked after endotoxin administration was studied in these rats. There were increased stains of ICAM-1 in endothelial cells and LFA-1 alpha in macrophages in the hepatic sinusoids in Propionibacterium acnes-pretreated rats compared with normal rats. Such stains were further increased soon after endotoxin administration, followed by development of hepatic necrosis. Monoclonal antibodies against both adhesion molecules significantly attenuated the extent of liver injury compared with controls, without affecting the infiltration and activation of hepatic macrophages. Polyclonal antibodies against polymorphonuclear leukocytes eradicated circulating neutrophils, but did not change such liver injury, although gum arabic, which suppressed macrophage activation, attenuated the extent of liver injury. Thus, adhesion between endothelial cells and activated macrophages in the hepatic sinusoids via ICAM-1 and LFA-1 alpha is essential for the initiation of massive hepatic necrosis of this type. Contribution of neutrophils seems less likely. (Hepatology 1996 Feb;23(2):320-8)

Covalent Binding of Oxidative Biotransformation Intermediates Is Associated with Halothane Hepatotoxicity in Guinea Pigs

In vivo covalent binding of halothane biotransformation-reactive intermediates to hepatic protein and lipid was examined in association with the subsequent development of hepatic necrosis in the guinea pig. Oxidative halothane biotransformation was inhibited by the use of deuterated halothane, whereas reductive metabolism was enhanced by low inspired oxygen concentrations. Male outbred Hartley guinea pigs (n = 8) were exposed to either 1% (v/v) halothane or deuterated halothane--with a fractional inspired O2 concentration (FIO2) of 0.40 or 0.10--for 4 h. Livers removed from half of the animals immediately after anesthesia were evaluated for organic fluorine bound to protein and lipid. The remaining animals were evaluated for a hepatotoxic response up to 96 h after exposure. Only guinea pigs that received 1% halothane at an FIO2 of 0.40 had centrilobular necrosis develop with significantly increased plasma alanine aminotransferase activities. All other treatment conditions significantly reduced oxidative halothane biotransformation, as indicated by decreased plasma trifluoroacetic acid concentrations. These reductions were associated with a significant decrease in organic fluorine bound to hepatic proteins. An FIO2 of 0.10 during halothane anesthesia significantly enhanced reductive biotransformation, as indicated by plasma fluoride ion concentrations. This was associated with a significant increase in organic fluoride bound to hepatic lipids. Centrilobular necrosis did not develop under these conditions. Thus, covalent binding to subcellular proteins by the trifluoroacetyl acid chloride intermediate generated by oxidative halothane biotransformation is implicated as a mechanism of centrilobular necrosis in guinea pigs. Binding to lipids by reductive pathway generated free radicals does not appear to be involved in production of the lesion.

Enflurane metabolism produces covalently bound liver adducts recognized by antibodies from patients with halothane hepatitis.

The existence of a rare syndrome of "enflurane hepatitis" similar to that described for halothane and of a cross-sensitization between halothane and enflurane has been controversial, largely due to equivocal clinical case reports and a lack of a plausible molecular mechanism for the hepatotoxicity. The present study suggests a possible hypersensitivity basis for enflurane hepatitis and the apparent cross-sensitization between halothane and enflurane involving covalently bound liver microsomal adducts. Immunoblotting studies have revealed that antibodies in the sera of six patients with halothane hepatitis recognize liver microsomal antigens of Mr = 100,000, or both 100,000 and 76,000, formed in rats treated with enflurane or halothane. These antigens were not detected in microsomes from isoflurane- or sesame oil-treated rats. The recognition of these antigens could be abolished by preincubation of the sera with microsomes from halothane-treated rats. These data suggest that the difluoromethoxydifluoroacetyl halide metabolite of enflurane, as well as the trifluoroacetyl halide metabolite of halothane, covalently bind to similar hepatic proteins, and may become immunogens in susceptible patients. This mechanism may also account for the apparent cross-sensitization between halothane and enflurane anesthesia, and the development of hepatic necrosis.

The involvement of endotoxin in halothane-associated liver injury.

Since endotoxin, lipopolysaccharides (LPS), have been implicated as a causative factor in the development of hepatic necrosis in rats exposed to hepatotoxic levels of several chemical agents, the role of LPS in the halothane-hypoxia (HH) model of hepatic damage in male Sprague-Dawley rats was investigated. When injected intravenously immediately after halothane anesthesia, a subnecrotic dose of LPS (0.5 mg/kg; Escherichia coli 026:B6) was found to markedly potentiate HH-induced hepatic necrosis. Pretreatment of the animals with the antiendotoxin agent, lactulose, prior to exposure to halothane reduced the hepatic damage normally seen from HH. A possible mechanism of LPS-induced potentiation was indicated by changes in hepatic calcium levels at 24 h after treatment. Endogenous LPS may play a role in HH-induced hepatic necrosis, and the mechanism of LPS-induced potentiation may be due to an LPS-related membrane dysfunction.

Characterization of hyperthyroidism enhancement of halothane-induced hepatotoxicity

Administration of anesthetic doses of halothane to hyperthyroid male rats results in the development of hepatic necrosis. The severity of the hepatic lesion was dependent on the dose of triiodothyronine (T 3) and the length of time it was administered. Pretreatment of rats with iodinated metabolites of thyroxin which do not induce hyperthyroidism did not result in any signs of hepatotoxicity after halothane exposure. The administration of halothane to hyperthyroid female rats or mice of either sex did not result in the development of any overt hepatotoxicity. Likewise, hyperthyroidism did not enhance the hepatotoxicity of another hepatotoxin bromobenzene. The in vitro enzymatic activities associated with cytochrome P-450-dependent metabolism and glutathione S-transferase conjugation activity were markedly altered in hyperthyroid rats. Cytochrome P-450 levels, aminopyrine N-demethylase activity, glutathione levels and glutathione S-transferase activity were all significantly lower in hyperthyroid rats. However, other enzyme activities were stimulated by T 3 pretreatment; aniline hydroxylase activity was increased by 45% and cytochrome c reductase activity was increased by 54% in hyperthyroid rats. Glutathione levels were also reduced significantly in hyperthyroid male rats. Maximal changes in both the cytochrome P-450 system and in the glutathione detoxification system were required before halothane demonstrated its hepatotoxic effects. Thus. a new balance between cvtochrome P-450-dependent bioactivation and glutathione conjugation of halothane may be necessary for the exaggerated hepatotoxicity of halothane seen in hyperthyroid male rats.

Glutathione Peroxidase System and Microsomal Lipoperoxidation in Prenecrotic Stages of Dietary Hepatic Necrosis in Rats

Simultaneous dietary deficiency of vitamin E and Se in weanling rats results in fatal hepatic necrosis. To investigate the possible relation between the state of hepatic cytosol glutathione peroxidase (GSH-Px) system (including glutathione reducA­ase,GSH-Rd, and glucose- 6-phosphate dehydrogenase, G-6-PD) and the hepatic microsomal lipo peroxidation (MLP), as well as the possible implications of these factors in the development of hepatic necrosis, weanling male rats were fed a basal diet low in Se and vitamin E, or were pair-fed with the same diet supplemented with either 3 mg/100 g diet of d/-a-tocopherol, with 0.36 mg/100 g diet of sodium selenite, or with both. Rats from the four groups were killed at 9, 20, and 26 days. At the late prenecrotic stage, GSH-Px activity in rats fed the basal diet alone was reduced by 97% and the in vitro MLP levels ( malonaldehyde ) were increased by seven-fold as com pared with rats fed the diet supplemented with Se and vitamin E. How ever, in vivo MLP (diene conjugation) was only detected in the liver of one rat that already had foci of necrosis at the time of killing. The decrease in GSH-Px was completely prevented by Se, but vitamin E had no effect. Dietary vitamin E and/or Se had little effect on the activity of GSH-Rd, but both agents, singly or in combination, prevented the reduction of G-6-PD that occurred in rats deficient in vitamin E and Se. The increased in vitro MLP was only partially reduced by either Se or vitamin E, since in both cases there still were three-fold increases. These results suggest that: a) no clear-cut relation exists between the massive decline of cytosol GSH-Px and the development of hepatic necrosis; b) the state of GSH-Px is probably unrelated to MLP; and c) microsomes may not be the initial site of damage. J. Nutr. 107: 1852-1858, 1977.

Centrolobular hepatic necrosis related to covalent binding of metabolites of halogenated aromatic hydrocarbons

The mechanism of centrolobular hepatic necrosis produced by treating rats or mice with 14C-labeled halogenated aromatic hydrocarbons was studied as an animal model of drug-induced tissue lesions. The development of hepatic necrosis was associated with the covalent binding of substantial amounts of radiolabeled material to liver proteins, and autoradiograms revealed that most of the covalently bound material was localized within the necrotic centrolobular hepatocytes. Prior induction of hepatic microsomal enzymes by phenobarbital administration potentiated the covalent binding and necrosis, whereas prior inhibition of hydrocarbon metabolism had the opposite effect, suggesting that the binding and necrosis are caused by toxic metabolites of the hydrocarbons. A positive correlation between the amount of covalent binding and the severity of centrolobular necrosis was obtained after various drug treatments and with several different halogenated benzene derivatives of varying hepatotoxicity. These results suggest that covalent binding of toxic metabolites may be an important mechanism in the pathogenesis of tissue lesions elicited by a variety of foreign compounds.

Antimicrobial agents in the prevention of dietary hepatic injury (necrosis, cirrhosis) in rats.

The effect of various antimicrobial agents, such as aureomycin, terramycin, streptomycin, chloromycetin, penicillin, polymyxin, and sulfaguanidine on the development of massive dietary necrosis of the liver in rats has been studied. Delay in the production of hepatic necrosis was obtained from aureomycin and, to a lesser extent, from terramycin and streptomycin. Indication of temporary protection was shown by sulfaguanidine, whereas chloromycetin, polymyxin, and penicillin were not protective. B(12), added alone, or in combination with aureomycin, to the basal experimental diet had no influence on the development of hepatic necrosis. A combination of pectin with streptomycin enhanced the protective effect of the antibiotic. All the antimicrobial agents tested, without relation to their effect on hepatic necrosis, produced temporary stimulation of growth in the experimental animals. The beneficial effect of aureomycin was not limited to the delay of hepatic necrosis but manifested itself also in the prevention of hepatic cirrhosis in rats fed a low protein (casein)-high fat diet. In contrast to control animals showing the usual combination of cirrhosis and renal changes, the rats receiving supplements of aureomycin were free of both cirrhosis and renal changes. The rats receiving aureomycin took more food in and gained weight. No microscopic alterations were seen in the pancreas of the control rats with cirrhosis. In both groups of experiments (necrosis and cirrhosis) the antimicrobial agents, with the exception of penicillin, were given mixed with the food. Their possible effect on the intestinal flora is discussed.