L. V. Kravchenko

Effects of Flavonoids on the Resistance of Microsomes to Lipid Peroxidation In Vitro and Ex Vivo

Incubation of rat liver microsomes with preparations of grape flavonoids, dihydroquercetin, and silibinin increased their resistance to lipid peroxidation induced by NADPH-Fe2++. This was manifested in less pronounced accumulation of lipid peroxidation products and changes in activity of microsomal enzymes induced by lipid peroxidation. In vitro antioxidant activity of grape flavonoids markedly surpassed that of dihydroquercetin and silibinin. Addition of flavonoids into fodder led to moderate, statistically significant, and similar increase in the resistance of rat liver microsomes to ex vivo induced lipid peroxidation.

Antioxidant status of rats receiving lycopene in different doses.

Oral treatment with lycopene (per os) in doses of 10 or 50 mg/kg for 2 weeks led to accumulation of lycopene in the liver, liver microsomes, and blood plasma, increased total plasma antioxidant activity, inhibited LPO in the liver, and decreased solubilization of lysosomal enzymes. Lycopene had no effect on ex vivo resistance of liver microsomes to LPO and activities of antioxidant enzymes in the liver.

Effect of Lactobacillus casei 114001 probiotic on bioactivity of rutin.

Male Wistar rats were maintained for 2 weeks on a semisynthetic ration with 0.4% rutin or on the same ration with 0.4% rutin and Lactobacillus casei 114001 suspension in physiological saline in a dose of 2×109 CFU per rat. Addition of Lactobacillus casei 114001 potentiated biological activity of rutin. Its antioxidant efficiency increased due to more pronounced increase in antioxidant capacity of the plasma, decrease in plasma content of LPO products, and more pronounced increase in reducing activity and antioxidant capacity of the cytosol of the liver and intestinal mucosa. The probiotic sharply increased the capacity of rutin to suppress procarcinogenic activity of bacterial β-glucuronidase.

Effects of Combined Treatment with Resveratrol and Indole-3-Carbinol

Male Wistar rats received a semisynthetic diet with resveratrol (100 mg/kg), indole-3-carbinol (20 mg/kg), or a mixture of these compounds in the same doses for 1 week. Activities of ethoxyresorufi n dealkylase (EROD), methoxyresorufi n dealkylase (MROD), pentoxyresorufin dealkylase (PROD), and 6β-testosterone hydroxylase (6β-TH) and the content of mRNA for CYP1A1, CYP1A2, and CYP3A1 were elevated in the liver o f rats receiving indole-3-carbinol. These changes were accompanied by an increase in activity of phase II xenobiotic metabolism enzymes (quinone reductase, hemoxygenase-1, glutathione transferase, and UDP glucuronosyl transferase). Resveratrol did not modify activity of these enzymes. After combined treatment with the test compounds, resveratrol suppressed the indole-3-carbinol-induced increase in activities of EROD, MROD, PROD, and 6β-TH, and expression of the corresponding genes. Combined treatment was characterized by potentiation of the antioxidant effects of these compounds.

Indole-3-Carbinol Induction of CYP1A1, CYP1A2, and CYP3A1 Activity and Gene Expression in Rat Liver under Conditions of Different Fat Content in the Diet

Wistar male rats were fed semisynthetic diet with different fat content for 6 weeks: fat-free, 10%, and 30% fat (sunflower oil and lard, 1:1). Increasing fat content was associated with an increase in ethoxyresofurin-O-dealkylase (EROD) activity of CYP1A1, methoxyresofurin-Odealkylase (MROD) activity of CYP1A2, and 6β-testosterone-hydroxylase (6β-TH) activity of CYP3A1. EROD, MROD, and 6β-TH activities in rats on high-fat diet exceeded those in rats on fat-free diet by 64, 58, and 140%, respectively. Addition of indole-3-carbinol to the diet led to an increase in CYP1A1, CYP1A2, and CYP3A1 activities and mRNA levels, the degree of this increase was lower with increasing fat content in the diet. In rats on fat-free, 10% fat, and 30% fat diets, indole-3-carbinol induced EROD activity by 4.7, 3.2, and 2.0 times, respectively; MROD activity by 5.9, 5.6, and 5.4 times; and 6β-TH activity by 2.1, 1.9, and 1.3 times. A correlation was detected between activities of the studied cytochrome P-450 isoforms, their inducibility by indole-3-carbinol, and vitamin A and E levels in rat liver.

Action of the mycotoxin of Fusarium sporotrichiella v. sporotrichioides on lysosomal membranes

The effect of the mycotoxin ofFusariumsporotrichiellav.sporotrichioides (sporofusarin) was studied in vitro on the total and nonsedimenting activity of eight lysosomal enzymes: acid ribonuclease, aryl sulfatases A and B, β-glucuronidase, α-and β-galactosidases, β-glucosidase, β-acetylglucosaminidase, and α-mannosidase. Incubation of a suspension of rat liver lysosomes with an aqueous solution of sporofusarin led to inhibition of the total activity of the membrane-bound lysosomal enzyme β-glucosidase. In a dose of only 1.6×10−5 M sporofusarin caused a significant increase in the nonsedimenting activity of nearly all the enzymes; in a concentration of 1.6×10−3 M most of the enzymes of the lysosomal matrix (β-glucuronidase, β-galactosidase, aryl sulfatases A and B) were liberated almost completely into the supernatant, and nearly all the β-glucosidase also was liberated. It is postulated that damage to the subcellular membranes is an important component of the toxic action of sporofusarin.

Effect of Lycopine on the Resistance of Rat Liver Microsomes to In Vitro Induced LPO

Lycopine in concentrations of 0.5-50 μM suppressed LPO in microsomes induced by NADPH-Fe2+ and by ascorbic acid-Fe2+. Lycopine in a concentration of 20 μM completely prevented the decrease in the rate of benz[a]pyrene hydroxylation and activation of p-nitrophenyl-UDP-glucuronosyl transferase caused by LPO induction in microsomes.

Investigation of the action of sporofusarin on cell membranes of the isolated perfused liver

The effect of sporofusarin (a myoctoxin produced byFusariumsporotrichiellav. sporotrichioides) on the functional activity and permeability of cell membranes of the isolated perfused rat liver was studied. Sporofusarin in a final concentration of 5.9·10−5 M was found to reduce the rate of bile formation, urea synthesis, and oxygen consumption and also to cause an earlier and severe disturbance of permeability of the lysosomal and plasma membranes of the hepatocytes (an increase in activity of the enzymes β-acetylglucosaminidase, β-glucuronidase, arylsulfatases A and B, and β-galactosidase in the supernatant of a liver homogenate and in the perfusion fluid). The depression of liver function by sporofusarin is considered to be the result of damage to the membraneous structures of the cell and, in particular, of the lysosomes.

Effect of mitomycin C and rubomycin C on nucleic acid metabolism in the rat liver

The dynamics of changes in the content of RNA and DNA and in the activity of acid r ibonuclease (RNase) and deoxyribonuclease (DNase) in the l iver of ra ts was studied at various t imes after administrat ion of LD~0 of mitomycin C and rubomycin C (daunomycin). Both antibiotics sharply reduced the RNA content in the liver within a few hours of their administrat ion. The DNA content remained virtually unchanged throughout the experiment (for 96 h). No correlat ion could be found between changes in the RNA content in the l iver of the experimental animals and acid RNase activity. It is suggested that an important role in the disturbance of nucleic acid metabol ism produced by both mitomycin C and rubomycin C is played by inhibition of RNA synthesis .

Activity of some mitochondrial and lysosomal enzymes of the guinea pig liver during sensitization and anaphylaxis

Noninbred male guinea pigs weighing about 200 g were used. The an imals were sens i t ized by a single subcutaneous injection of 0.02 ml no rma l horse s e r u m (NHS) in a dose of 0.7 mg prote in/100 g body weight. Lethal anaphylact ic shock was induced in the sens i t i zed an imals a f t e r 25 days, acute shock by in t r aca rd i ac injection of 1 mI NHS (35 mg pro te in /100 g), and p r o t r a c t e d shock by in t raper i tonea l injection of 2 ml NHS (70 mg pro te in /100 g). The control (unsensitized) an imals we re injected with the equivalent dose of NHS. After l apa ro tomy under local anes thes ia , l i ve r biopsy was p e r f o r m e d during acute shock before and a f te r injection of the reac t ing dose (at the 7th-10 minute), and during p ro t r ac t ed shock before and 1.5-2 h a f t e r the injection.