Betulin attenuated liver damage by prevention of hepatic mitochondrial dysfunction in rats with alcoholic steatohepatitis.

Betulin, a pentacyclic triterpene, possesses antioxidant, anti-inflammatory and hepatoprotective properties. The aim of this study was to evaluate the impact of liver mitochondria in hepatoprotection of betulin using a rat model of alcoholic steatohepatitis induced by ethanol administration (4 g/kg, intragastric) for 8 weeks. The treatment with betulin (50 and 100 mg/kg b.w., intragastric) during this period attenuated the histological signs of steatohepatitis and lowered the serum and liver triglyceride contents, as well as the serum activities of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. Betulin (100 mg/kg) decreased the liver/body weight ratio and inhibited the increase in the serum levels of TNFα, IL-1ß, TGFß, and hyaluronic acid, demonstrating hepatoprotective, anti-inflammatory, and antifibrotic potential. Betulin also inhibited the formation of superoxide anions in mitochondria and the end-products of lipid peroxidation in liver tissue, the amount of which was significantly increased in ethanol-treated rats. The disturbances in mitochondrial respiration, uncoupling of oxidative phosphorylation and decreasing of mitochondrial complex I, II, and IV activities in rats with steatohepatitis, were reverted by betulin administration. The increased susceptibility of mitochondria to Ca2+-induced permeability transition pore formation in the hepatitis group was improved in rats treated with betulin. In conclusion, betulin, having antioxidant properties, exerts a beneficial effect in the rat model of alcoholic steatohepatitis via prevention of liver mitochondria dysfunction, which may be attributed to the inhibition of mitochondrial permeability transition.

[Preventive administration of new UDCA derivatives in experimental alcoholic steatohepatitis].

We have studied the prophylactic effect of new derivatives of ursodeoxycholic acid (UDCA), including UDCA-N-acetylcysteine, UDCA-L-acetylcysteine, and nor-UDCA (in doses equivalent to 40 mg/kg of UDCA) on the development of experimental alcoholic steatohepatitis induced by the Lieber-DeCarli liquid ethanol-containing diet. Results demonstrated that most of the investigated compounds produced a hepatoprotective effect, improving biochemical tests and liver morphology, as manifested by decreasing steatosis intensity, activity of alkaline phosphatase and gamma-glutamyltranspeptidase, triglyceride level in blood serum and liver, and TNF alpha content. However, nor-UDCA was most effective as compared to UDCA in preventing the accumulation of triglycerides in the liver.

[Hepatoprotective and immunomodulatory effects of infliximab on experimental alcoholic steatohepatitis].

The effect of infliximab (1 and 10 mg/kg, i.p., during 10 days) on alcoholic steatohepatitis has been studied in rats fed with ethanol-containing liquid diet over 10 weeks. Both doses of infliximab showed immunomodulatory and anti-inflammatory effects, whereas only the maximum drug dose significantly decreased lipid accumulation in the liver. It can be concluded that infliximab (10 mg/kg) acts as an effective hepatoprotector, anti-inflammatory agent, and immunomodulator in rats with experimental alcoholic steatohepatitis.

Reversal of experimental ethanol-induced liver steatosis by borage oil.

The aim of study was to evaluate the hepatoprotective effect of borage oil containing predominantly gamma-linolenic acid in rats with alcoholic steatohepatitis. Liver of ethanol-treated animals was characterized by fatty and hydropic dystrophies. Liver triglyceride contents and activitiies of serum marker enzymes were significantly increased. Ethanol increased nicotinamide adenine dinucleotide phosphate hydrogen (NADPH)-induced chemiluminescence and the contents of liver thiobarbituric acid reactive substances (TBARS). The reduced glutathione content in the liver was decreased. Ethanol enhanced liver microsomal cytochrome P-450 (CYP450) content, aniline p-hydroxylase and amydopyrine-N-demethylase activities. The treatment with borage oil improved the liver morphology, decreased triglyceride contents and normalized serum marker enzyme activities. Borage oil developed an antioxidant effect in ethanol-treated rats. The treatment with this compound decreased NADPH-induced chemiluminescence and the content of lipid peroxidation products. Borage oil normalized CYP450 content compared with the ethanol-treated group. CYPI450 2E1 isoform is a main source of free oxygen radicals in the liver of ethanol-treated rats and we propose that the antioxidant effect of borage oil is realized via the normalization of CYP450 content and activities of CYP450-related microsomal oxidases, as borage oil can improve the lipid surrounding of CYP450. In our opinion, the hepatoprotection by borage oil in alcoholic steatosis is connected with its antioxidant properties.

Inhibition of inducible nitric oxide synthase activity prevents liver recovery in rat thioacetamide-induced fibrosis reversal.

BACKGROUND: Stimulation of nitric oxide (NO) synthesis similar to the application of NO donors could be of benefit in liver fibrosis. Many authors believe that activation of NO synthesis by pharmacological agents is promising in the treatment of liver fibrosis. However, there is considerable controversy in understanding the role of NO in fibrogenesis and fibrolysis. The aims of our study were to evaluate the effects of L-arginine, as an NO metabolic precursor, and those of NO synthase (NOS) inhibitors, L-nitroarginine methyl ester (L-NAME) and aminoguanidine (AG) in rats with thioacetamide (TAA)-induced liver fibrosis reversal. MATERIALS AND METHODS: Male Wistar rats, 230-240 g, received TAA (200 mg kg(-1), intraperitoneally) twice a week for 3 months. Liver resolution was simulated by withdrawal of TAA administration. Thereafter the animals were subdivided into five groups and treated by intragastric intubation with: L-arginine (100 and 300 mg kg(-1)); L-NAME as an inhibitor of both constitutively expressed NOS (eNOS) and inducible NOS (iNOS) (20 mg kg(-1)), AG as a specific inhibitor of iNOS (100 mg kg(-1)) or placebo. The severity of liver fibrosis was assessed by morphometric evaluation of liver slides stained with Azan-Mallory, hydroxyproline (Hyp) determination and mRNA steady state levels of collagen I, transforming growth factor (TGF)-beta1, metalloproteinases (MMP)-13, -14, tissue inhibitor of MMP (TIMP)-1 and plasminogen activator inhibitor (PAI)-1 were quantified by real time PCR. The activities of serum marker enzyme, alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase, were measured. RESULTS: TAA treatment during 3 months induced micronodular liver fibrosis with a pronounced deposition of collagen fibres. L-Arginine did not affect this deposition nor did it affect both relative and total liver hydroxyproline content. Both NOS inhibitors significantly increased the square of the liver connective tissue stained by Azan-Mallory and the above parameters characterizing liver hydroxyproline content. Both NOS inhibitors up-regulated procollagen alpha1 (I), MMP-13, TIMP-1 and PAI-1 mRNA expression. The AG effects were more pronounced. than those of L-NAME. AG treatment also increased mRNA expression of TGF-beta1 and PAI-1. CONCLUSIONS: Both NOS inhibitors developed a clear pro-fibrotic effect in the liver. Aminoguanidine was more fibrotic than L-NAME. Our data suggest a significant anti-fibrotic role for iNOS rather than for eNOS. L-Arginine did not show any anti-fibrotic properties in the TAA-model used.

[Antioxidative effects of isoflavon genisteine-8-C-glycoside in vitro and in vivo].

Bioflavonoids (polyhydroxyphenols) are ubiquitous components of plants, fruits and vegetables; these compounds are efficient scavengers of free oxygen radicals and peroxides. The aim of this study was to investigate the antioxidative effects of genistein-8-C-glycoside (G8CG) isolated from the flowers of Lipinus luteus L. G8CG dose-dependently inhibited membrane lipid peroxidation and prevented GSH oxidation in human red blood cells and rat liver homogenates under tert-butylhydroperoxide-induced oxidative stress and single whole-body gamma-irradiation (1 Gy) of rats.

Antioxidant mechanism of hepatoprotection by ursodeoxycholic acid in experimental alcoholic steatohepatitis.

PURPOSE: The aim of this study was to evaluate the role of an antioxidant factor in the hepatoprotective effect of ursodeoxycholic acid (UDCA) in rat alcoholic steatohepatitis. MATERIAL AND METHODS: The effects of UDCA (40 mg/kg, i.g., 30 days) were studied using rats fed on a high-fat diet (52% calories as fat) and administered with ethanol via intragastric intubation (4 g/kg daily, 30 days). RESULTS: The livers of ethanol-treated animals were characterized by fatty dystrophy. The relative liver weight and the square of the sudanophylic area as well as the liver triglyceride content and the activity of the serum marker enzymes, aspartate aminotransferase and gamma-glutamyltransferase, were significantly increased. Elevated superoxide dismutase activity as well as increased contents of lipid peroxidation products (hydroxyalkenals, malone dialdehyde, etc.) and lucigenin-enhanced microsomal chemiluminescence were observed in the liver of ethanol-treated rats and the liver reduced glutathione content was decreased. An increase in monoenoic fatty acids, a decrease of the n-6 acid family and an enhancement of microsomal membrane viscosity were found in the liver of these animals. An elevation of the total cytochrome P-450 content and the activity of amidopyrine-N-demethylase were shown in liver microsomes of the ethanol-treated group. The UDCA treatment improved the liver morphology, decreased serum marker enzyme activities, liver triglyceride content and normalized all the indices of oxidative stress. UDCA lowered the viscosity of the microsomal membrane, as assessed by both the fluorescence probe techniques and the saturated/unsaturated fatty acid ratio. The microsomal cytochrome P-450 content and amidopyrine-N-demethylase activity were normalized in UDCA-treated rats. CONCLUSIONS: We can conclude that the hepatoprotective effect of UDCA stipulated by its antioxidant properties is indeed the factor enabling UDCA to control metabolic processes by changing the properties of liver membranes and membranous proteins.

Effect of the nitric oxide donor and the nitric oxide synthase inhibitor on the liver of rats with chronic hepatitis induced by dimethylnitrosamine.

The present study was designed to examine the effects of the donor of nitric oxide (NO), NaNO(2) and the inhibitor of NO synthase, N(omega)-nitro-L-arginine (L-NNA), on the development of dimethylnitrosamine (DMNA)-induced chronic hepatitis in rats. L-NNA decreased rat survival and enhanced the severity of hepatic encephalopathy in the DMNA-treated animals. The aggravation of the morphological signs of hepatitis, the activation of serum alanine aminotransferase and cytosolic superoxide dismutase activities and the increase in the liver malondialdehyde content were observed in this group. The treatment with NaNO(2) improved liver morphology, decreased serum marker enzyme activities, lowered the activities of alpha-D-mannosidase and N-acetyl-beta-D-glucosaminidase compared to the DMNA-treated group. The results of the morphological and biochemical studies suggest that L-NNA increased DMNA-induced liver damage, whereas NaNO(2) partially prevented the development of chronic hepatitis. It is proposed that the opposite effects of L-NNA and NaNO(2) are partially explained by a modulation of the free radical-dependent processes in the liver.

[The influence of panthotenic acid mitochondrial oxidation and oxidative phosphorylation in liver of rats with alimentary obesity]. / Vliianie proizvodnykh pantotenovoi kisloty na mitokhondial'noe okislenie i okislitel'noe fosforilirovanie v pecheni krys s alimentarnym ozhireniem.

Alimentary obesity induced by the long-term feeding of rats by high-fat diet results the reducing of rate and efficiency of oxidative phosphorylation in liver mitochondria when NAD-dependent substrates are used. The treatment of the obese rats with panthotenic acid derivatives (phosphopantotenate, panthetin, panthenol) enhanced oxidative phosphorylation of pyruvate and fatty acid carnitine esters. Among investigated compounds panthenol activated respiratory control and phosphorylation rate more effectively. Moreover, panthenol, but not phosphopanthotenate nor panthetine, increased the activity of carnitine palmitoyltransferase 1 that confirms the preferable usage of fatty acids for mitochondrial oxidation under the influence of this compound.

[Dynamics of structural changes in rat liver after single dose of gamma-irradiation]. / Dinamika strukturnykh izmenenii v pecheni krys posle odnokratnogo vozdeistviia gamma-izlucheniia.

Histological changes and alterations in biophysical and biochemical parameters in liver of gamma-irradiate rats have been investigated. The gamma-irradiation of the whole body of rats with a single dose of 1 Gy did not cause any impairments of beam structure of rat liver, but resulted in the lymphocytic infiltrations of portal tracts which were not accompanied by formation of spotty areas of necrosis in adjacent areas of lever parenchyma. gamma-Irradiation stimulated proliferation of the hepatocytes and induced time-dependent mitochondrial structure lesions. Post-irradiation changes in cell cytoplasm appeared as disordering in reticulum-endothelial system, among them enlarging and fragmentation of its cisterns, cytoplasmic vacuolization, enhancement of the number of lysosomes and of the lipid inclusion contents. These facts revealed the mobilization of the additional energy resources for recovery of metabolic processes in rat liver. Post-irradiation increase of the level of the hepatocyte membrane lipid peroxidation products preceded liver morphological alterations. The membrane lipid microviscosity decreased in 1 and 3 days after irradiation. As a result of damages of hepatocyte membrane, the activity of the alanin- and asparagin-aminotransferases in blood serum increased 6 hours after. We can conclude that the whole body single gamma-irradiation with a dose of 1 Gy leads to the reversible but significant damages to the rat liver cell membrane structures. These damages might be the reason of radiation-induced liver morphological alterations.

Antioxidative effect of ursodeoxycholic acid in the liver of rats with oxidative stress caused by gamma-irradiation.

We studied effects of ursodeoxycholic acid (UDCA) (10 and 100 mg/kg b.w.) on the free radical generation, lipid peroxidation and the antioxidant defense system in the liver of rats with oxidative stress caused by gamma-irradiation. Both doses of UDCA normalized the liver parameters enhanced by gamma-irradiation: the content of superoxide anion and carbonyl-containing products of lipid peroxidation (alkanals, alkenals, alkadienals and ketones), the superoxide dismutase activity and the chemiluminescence enhanced by luminol. Only the highest dose of UDCA (100 mg/kg b.w.) decreased the chemiluminescence enhanced by lucigenin in liver microsomes and the hydroxyalkenals content in the liver. UDCA prevented reduced glutathione depletion caused by gamma-irradiation, whereas glutathione-related enzyme activities did not change under the influence of both the UDCA doses as well as gamma-irradiation. Thus, the data obtained suggest that UDCA is a metabolite having the sufficiently effective antioxidant properties.

Effect of ursodeoxycholic acid on prostaglandin metabolism and microsomal membranes in alcoholic fatty liver.

The aim of the present study was to evaluate the effect of ursodeoxycholic acid (UDCA) on prostaglandin and fatty acid metabolism and the possible relation of these substances to the development of alcoholic fatty liver in rats. The effects of UDCA (40 mg/kg/day, 30 days) were studied in rats pair-fed a high-fat diet (52% of calories as fat) with daily ethanol (4 g/kg/day, 30 days) intragastric intubation. The livers of ethanol-treated animals were characterized by fatty dystrophy. Liver triglyceride and cholesterol ester contents and the activities of serum marker enzymes, alanine aminotransferase and gamma-glutamyltransferase, were significantly increased. Ethanol enhanced phosphoinositol and sphingomyelin content in liver microsomes and lowered prostaglandin E(2) (PGE(2)) concentration in the liver. An increase in the percentage of monoenoic fatty acids and a decrease in the n-6 acid family in liver phospholipids, linoleoyl-CoA desaturase, and PGE(2) synthase activities in liver microsomes were observed in ethanol-treated rats. Treatment with UDCA improved liver morphologic characteristics, decreased triglyceride and cholesterol ester contents, increased the PGE(2) level, and normalized linoleoyl-CoA desaturase and PGE(2) synthase activities, as well as phospholipid and fatty acid patterns in the liver. The activities of the serum marker enzymes were decreased in the ethanol- and UDCA-treated group. Ursodeoxycholic acid lowered the viscosity of the microsomal membrane, as assessed by both fluorescence probe techniques and the saturated/unsaturated fatty acid ratio. We propose that the hepatoprotective effect of UDCA in alcoholic fatty liver is related to the stabilization of microsomal membranes, the prevention of a decrease in essential fatty acids and PGE(2) in the liver, and, probably, an improvement in biochemical processes controlled by PGE(2).

[Effect of gamma-linolenic acid on microsomal oxidation in the rat liver following gamma-irradiation]. / Vliianie gamma-linolenovoi kisloty na sistemu mikrosomal'nogo okisleniia pecheni krys pri gamma-obluchenii.

The antioxidant and radioprotector properties of gamma-linolenic acid isolated from the seeds of Borago officialis were studied on rats gamma-irradiated to a dose of 1 Gy. The irradiation caused an increase in the content of malonaldehyde in microsomal liver fraction and disturbed the metabolism of xenobiotics. The administration of gamma-linolenic acid in the form of a commercial drug Neoglandin (daily dose, 150 mg/kg, p.o.; over 1, 3, or 7 days after irradiation reduced the level of lipid peroxidation (for all treatment schedules), normalized the activity of NADPH-oxidase, NADH-oxidase, and NADPH-reductase, and increased the content of cytochromes P-450 and b5 as compared to bothirradiated and control animals.

[Antioxidant effect of prostaglandin E2 in the liver alcoholic steatosis]. / Antioksidantnye svoistva prostaglandina E2 pri alkogol'nom steatoze pecheni.

The mechanisms of the antioxidant effect of prostaglandin E2 (PGE2) in cases of chronic alcoholic intoxication were studied. It is shown that PGE2 decreases the production of hydroxyl radicals, lipoperoxides, conjugated dienes, malonic dialdehyde, and carbonyl-containing products of lipid peroxidation. In addition, PGE2 normalizes activity of the liver microsomal monooxygenase system components responsible for the free oxygen radical production.

Antiatherogenic effects of 17 beta-estradiol and 17 alpha-estradiol and its derivative J811 in cholesterol-fed rabbits with thyroid inhibition.

OBJECTIVE: The aim of this study was to investigate the antiatherogenic effects of 17 beta-estradiol and 17 alpha-estradiol and its derivative J811 (estra-1,3,5(10),8-tetraene-3, 17 alpha-diol), having a non-feminizing effect and high antioxidant potential, in male rabbits. EXPERIMENTAL DESIGN: Male White-Russian rabbits weighing 2.1-2.6 kg were fed either a standard or a high-cholesterol (200 mg/kg) diet, with thyroid function-inhibiting thiouracil (20 mg/kg) combined with cholic acid (40 mg/kg) administered daily in sunflower oil for 3 months. During the last month of the study, estrogens were administered by gavage at a dose of 0.02 or 0.1 mg/kg. RESULTS AND CONCLUSIONS: All three estrogens exerted remarkable antiatherosclerotic effects. Decreases in serum and aortic-wall lipid parameters and the index of atherogenicity were dependent on estrogen dose. Morphological evaluation of the aortic wall (height of plaques, size of plaque relative to aortic half-circumference) showed only weak therapeutic effects with all three estrogens. It is an open question whether the treatment period was too short to reverse the above changes. On the other hand, the data clearly suggest that 17 alpha-estradiol and J811 offer new perspectives for the prevention of atherosclerosis in men, which is similar to that found with 17 beta-estradiol in women.

Hypolipidemic effect of pantothenic acid derivatives in mice with hypothalamic obesity induced by aurothioglucose.

The hypolipidemic effects of pantothenic acid derivatives (phosphopantothenate, panthenol and pantethine) were studied in mice with hypothalamic obesity. Hypothalamic obesity in mice was induced by single injection of aurothioglucose (300 mg/kg body wt, i.p.). All the tested substances were administered during the last 10 days before decapitation (i.m., of dosage equivalent to 150 mg/kg body wt of phosphopantothenate). The studied substances inhibited the weight gain of the animals with hypothalamic obesity over the last 10 days of the experiment. The treatment with aurothioglucose increased food intake and mean body weight, blood glucose level; insulin, serum total cholesterol, triglyceride, the sum of LDL + VLDL and LDL-cholesterol concentration; triglyceride and cholesterol fractions in the liver; triglyceride and FFA content as well as lipoprotein lipase activity in adipose tissue of experimental mice. The administration of the assay compounds lowered food intake and mean body weight, insulin and glucose levels and decreased the content of triglycerides, total cholesterol and cholesterol esters in serum and adipose tissue as well as raised the activity of lipoprotein lipase in adipose tissue and serum lipolytic activity in obese mice. Among the compounds studied the reverse effect of panthenol was especially pronounced. The mechanism of hypolipidemic effects of pantothenic acid derivatives can be related to the reduced resistance to insulin and activation of lipolysis in serum and adipose tissue.

Hypochlorous acid-induced lysis of human erythrocytes. Inhibition of cellular damage by the isoflavonoid genistein-8-C-glucoside.

Erythrocyte damage induced by hypochlorous acid (HOCl) results in cell lysis developing with time after the oxidant is removed (post-hemolysis). The apparent rate constant of post-hemolysis depends on time of incubation in the presence of HOCl and concentration of this oxidant. HOCl-dependent damage of erythrocyte membranes is associated with uncompetitive inhibition of the membrane-bound acetylcholinesterase. Genistein-8-C-glucoside is an isoflavonoid isolated from the flowers of Lupinus luteus L.; in aqueous solution, genistein-8-C-glucoside (0.5-2 mM) efficiently inhibited HOCl-induced damage to erythrocytes similar to the known HOCl scavengers taurine and reduced glutathione. This bioflavonoid can protect the erythrocyte membrane (and to a lesser extent, intraerythrocytic components) by interacting with the reactive chlorine species including hypochlorous acid and membrane-bound chloroamines formed in the reaction of HOCl with erythrocyte membrane proteins.

[The functional activity of the adrenocortical system and the transcortin-binding capacity of the blood plasma in rats during the development of tolerance to the narcotic action of ethanol]. / Funktsional'naia aktivnost' adrenokortikal'noi sistemy i sviazyvaiushchaia sposobnost' transkortina plazmy krovi krys pri razvitii tolerantnoosti k narkoticheskomu deistviiu étanola.

Corticosterone levels were studied using HPLC in the blood plasma and tissues of rats after 1, 4, 7 and 10 injections of ethanol (3.5 g/kg, daily). Main parameters of binding of corticosteroid-binding globulin (CBG) were calculated using Scatchard's plots. It is shown that development of tolerance to the hypnotic action of ethanol in rats is accompanied with: 1) increased levels of corticosterone in the adrenal tissue, 2) gain of the adrenals' weight, 3) inhibition of the stressogenic elevation of corticosterone plasma levels, 4) decline in the binding capacity of plasma CBG, 5) reduced concentration of dexamethasone-sensitive steroid receptors in the liver. Negative correlations between the duration of ethanol-induced sleep and concentration of corticosterone were found: for adrenal tissue after 7 and for plasma after 10 injections of ethanol (24 hours after the injection).