[Effects of polyphenols on activity of glycosyl hydrolases in the cecum of rats fed obesity inducing diets].

The results of experimental studies indicate that the preventive and therapeutic effects of polyphenols in obesity are accompanied by a significant decrease in the severity of dysbiosis caused by the predominance of fats and simple carbohydrates in the diet, especially fructose, and the restoration of the functional state of the microbiota. The aim of the work was to study the effect of quercetin and resveratrol - polyphenols, widely represented in the daily human diet, on the activity of bacterial glycosidases in rats receiving diets high in fructose or fat and fructose. Material and methods. Using spectrophotometric analysis, the activity of ß-galactosidase (Gal), ß-glucosidase (Glu) and ß-glucuronidase (Gluс) was studied in the content of the cecum of Wistar rats receiving a semi-synthetic diet and a 20% solution of fructose instead of drinking water (hfr diet) or a semi-synthetic diet with a high (30%) fat content and a 20% solution of fructose instead of drinking water (hf/hfr diet). Results and discussion. Feeding rats with the hfr diet for 20 weeks led to the suppression of Gal activity by 35, Glu by 46 and Gluс by 31%. With the inclusion of quercetin in the hfr diet at a dose of 34 mg/kg b.w. enzyme activity was restored to the control values and exceeded the level of activity in rats fed hfr ration without quercetin by 60, 100 and 47%, respectively, for Gal, Glu, and Gluс. Feeding rats with the hf/hfr diet for 10 weeks did not have a significant impact on the activity of bacterial enzymes. The inclusion of resveratrol in the hf/hfr diet at a dose of 10 mg/kg b.w. resulted in a decrease in Glu activity by 58 and Gluс by 28%, and an increase in resveratrol dose to 100 mg/kg b.w. caused further suppression of Gal activity by 30, Glu by 76 and Gluc by 64% comparative to the activity in rats on the hf/hfr diet without resveratrol. Conclusion. The obtained data suggest that quercetin restores reduced by hfr diet activity of glycosyl hydrolases of the cecum microflora of rats, most likely due to an increase in the representation of the types of enzyme activity carriers. The suppressive effect of resveratrol on the activity of glycosyl hydrolases of the cecum microflora of rats fed a hf/hfr diet may be the result of its direct action on enzymes and is not associated with the effect on the composition of the intestinal microbiota.

[Effects of quercetin on protective capacity in rats fed a high-fructose diet].

The purpose of the study was to determine effects of quercetin on protective capacity parameters in the experiment on rats fed a high fructose diet. Rats of the control group received a semi-synthetic (s/s) diet and water; animals from the 1st experimental group - s/s diet and 20% fructose solution instead of drinking water; rats of the 2nd experimental group- s/s diet with quercetin (0.1% indiet) and 20% fructose solution instead of drinking water for 20 weeks. Parameters of antioxidant status [total antioxidant activity (AOA), the content of malondialdehyde (MDA) and lipids hydroperoxides, the level of reduced and oxidized glutathione, activity of superoxide dismutase, catalase, glutathione peroxidase, paraoxonase-1, hemeoxygenase-1, NAD(P)H-quinone oxidoreductase], the activity of xenobiotic-metabolizing enzymes [CYP1A1, CYP1A2, CYP2B1, CYP3A, UDP-glucuronosyltransferase (UDP-GT) and glutathione transferase] were studied in plasma and liver of rats. Consumption of the high-fructose diet led to changes in some parameters: diminution of AOA in blood plasma, decrease of AOA and MDA level, unsedimentable activity of lysosomal enzymes, increase of the UDP-GT activity in liver. The inclusion of quercetin in the diet did not affect the studied parameters, except for a more pronounced decrease of the unsedimentable activity of lysosomal enzymes in rat liver. The results of the study indicated that there was no significant effect of quercetin on the protective capacity of rats at the initial stage of obesity caused by high-fructose diet.

[Toxicological evaluation of colloidal nano-sized silver stabilized polyvinylpyrrolidone. III. Enzymological, biochemical markers, state of antioxidant defense system].

Nanosized colloidal silver (NCS) with primary nanoparticles (NPs) size in the range of 10-80 nm in aqueous suspension was administered to rats with initial weight 80±10 gfor the first 30 day intragastrically and for lasting 62 days with the diet consumed in doses of 0.1; 1.0 and 10 mg/kg of body weight b.w) per day based on silver (Ag). The control animals received deionized water and carrier of NPs - aqueous solution of stabilizer polyvinylpyrrolidone. Activity (Vmax) was determined in liver of microsomal mixed function monooxygenase isoforms CYP 1A1, 1A2 and 2B1 against their specific substrates, the activity of liver conjugating enzymes (glutathione-S-transferase and UDP-glucuronosyltransferase) in the microsomal fraction and a cytosol, and the overall and non-sedimentable activities of lysosomal hydrolases. In blood plasma there were evaluated malonic dialdehyde, PUFA diene conjugates, in erythrocytes - the activity of antioxidant enzymes. A set of standard biochemical indicators of blood serum was also determined. The studies revealed changes in a number of molecular markers of toxic action. Among them - the increase in the activity of key enzymes I and II stages of detoxification of xenobiotics, indicating its functional overvoltage; reducing the activity of glutathione peroxidase (GP), the total arylsulfatase A and B, ß-galactosidase (in the absence of changes in their non-sedimentable activity), levels of uric acid, increased alkaline phosphatase activity. These changes occurred mainly at the dose Ag of 10 mg/kg b.w., except for the GP to which the threshold dose was 1 mg/kg b.w. No significant changes in the studied markers in a dose Ag 0,1 mg/kg b.w. were identified. Possible mechanisms of the toxic action of silver NPs are discussed.

[Effects of rutin on protective capacity in rats].

The purpose of the study was to determine effects of rutin dietary administration on the activity of xenobiotic-metabolizing enzymes and antioxidant status. The study has been carried out on 3 groups of male Wistar rats (n = 8 in each), with initial body weight 100-120 g. Animals of the control group (1st group) received standard semi-synthetic diet, the experimental groups--the same diet with rutin in the amount of 40 mg/kg b.w. (2nd group) or 400 mg/kg b.w. (3rd group). The duration of the experiment was 2 weeks. In rat liver the activity of quinone reductase (QR), heme oxygenase-1 (HO-1), paraoxonase-1 (PON-1), glutathione-S-transferase (GST), ethoxyresorufin-O-dealkylase (EROD) activity of CYP1A1, methoxyresorufin-O-dealkylase (MROD) activity of CYP1A2, tes- tosterone 6ß-hydroxylase (6ß-TG) activity of CYP3A, total antioxidant activity (AOA) and malondialdehyde (MDA) content have been investigated. The expression of genes CYP1A1, CYP1A2 and CYP3A has been measured by reverse transcription-polymerase chain reaction (RT-PCR). The stability of lysosome membranes was estimated by the change of unsedimentable activity of lysosomal enzymes--arylsulfatase, ß-galactosidase and ß-glucuronidase. Rutin administration led to dose-dependent increase in the activity of antioxidant enzymes. In rats of the 3rd group received high-rutin diet the activity of QR, HO-1, PON-1 and GST increased by 68, 29, 17 and 22%, respectively, compared to the control (1st group); MDA level and AOA have not changed. Activity of EROD and MROD in liver microsomes of rats treated with rutin at a dose of 40 mg/kg b.w. (2nd group) increased by 33 and 58%, respectively, with a moderate increase in mRNA level of CYP1A1 and CYP1A2. Increasing the dose of rutin up to 400 mg/kg b.w. (3rd group) resulted in the decrease of the degree of EROD and MROD activation by 18 and 15%, respectively, compared to the 2nd group. Rutin had no significant effect on the activity of 6ß-TG and on the expression of CYP3A1 gene. Rutin dietary administration led to dose-dependent reduction of the unsedimentable activity of lysosomal enzymes, indicating the strengthening of the stability of lysosomal membranes. Thus, the obtained results showed that in healthy, intact rats high doses of rutin in the diet moderately but statistically significantly activate enzyme systems responsible for the protective and adaptive capacity of the organism.

[Effects of rutin on the activity of antioxidant enzymes and xenobiotic-metabolizing enzymes in liver of rats fed diets with different level of fat].

The study has been carried out on 6 groups of male Wistar rats, which received semi-synthetic diets within 28 days. Rats of 1st and 4th group received fat-free diet, 2nid.and 5th - diet containing standard amount of fat (10% by weight, 26% by caloric content; lard/sunflower oil - 1/1); 3rd and 6th group - a high-fat diet (30% by weight, 56% by caloric content). During the last 14 days of the experiment rats received rutin in the dose of 40 mg/kg b.w. AOA, MDA level and the activity of paraoxonase I have been evaluated in blood serum. In rat liver along with the parameters of the antioxidant status (MDA level, activity of paraoxonase 1, quinone reductase, heme oxygenase-1) the activity of xenobiotic-metabolizing enzymes (XME) (CYP1A1, CYP1A2, CYP3A1, CYP2B1, UDP-glucuronosyl transferase and glutathione transferase) and the activity of lysosomal enzymes (arylsulfatase A and B, ß-galactosidase and ß-glucuronidase) have been investigated. Elevation of the activity of antioxidant enzymes and XME in liver with the increase of diet fat content has been-noted. Rutin admihistration had no effect onparamete6rs of antioxidant status and decreased unsedimentable activity of lysosomal enzymes that did not depend on fat content in the diet. Rutin receiving increased the activity of all studied XME in rats fed standard diet, but practically did not effect on their activity in rats fed by fat-free and high-fat diets. Thus, rutin in pharmacological dose has no effect on the activity of antioxidant enzymes that doesn't depend on the level of fat in the diet, while the decrease or increase of diet fat content modulates (weakens) the influence of rutin on the XME activity.

[Effects of omega-3 polyunsaturated fatty acids on antioxidant capacity in rats].

Dietary administration of omega-3 polyunsaturated fatty acids (EPA + DHA, 1,2:1) at dose 0.3 or 1 g/kg bw during 4 weeks led to minor (by 14% and 17%, p<0.05) decrease of serum antioxidant capacity and serum level of vitamin E (by 30% and 31%, p<0.05) and the activity of paraoxonase-1 (by 14% at 0.3 g/kg bw, p<0.05). The activity of antioxidant enzymes in liver increased in a dose-dependent manner. At higher dose of omega-3 polyunsaturated fatty acids a 45% increase in the activity of paraoxonase-1 (p<0.05), 21% -heme oxygenase-1 (p>0.05), 68% - quinone reductase (p<0.05), 19% - glutathione S-transferase (p<0.05) compared to the control group was found. The direct relationship between activities of enzymes and increase of MDA level in liver (by 47 and 107%, p

[Effects of dietary fat level on the xenobiotic metabolism enzymes activity and antioxidant enzymes in rats].

Male Wistar rats received fat-free diet or diets containing 5, 10 and 30% of fat (sunflower oil + lard, 1:1) for 4 weeks. The direct relationship between dietary fat level and ethoxyresorufin O-dealkylase activity of CYP1A1, methoxyresorufin O-dealkylase activity of CYP1A2, pentoxyresorufin O-dealkylase activity of CYP2B1 and testosterone 6beta-hydroxylase activity of CYP3A was found. Activities of key enzymes of phase II xenobiotic metabolism (total activity of glutathione transferase, activity of UDP-glucuronosyle transferase) and antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase, paraoxonase-1 and heme oxygenase-1) also increased with higher dietary fat level.

[Characterization of fullerene C60 peroral toxicity to rats in the 92-day experiment].

Toxicity of fullerene C60 in male Wistar rats under conditions of a daily intragastric administration at doses of 0.1; 1 and 10 mg/kg body weight for 92 days was studied. Integral, biochemical, physiological, hematological, immunological indicators were determined that characterized the body condition of animals together with fullerene C60 biodistribution in organs and tissues of rats. Majority of the results didn't show any influence of fullerene C60 on animals treated with it in the whole range of doses studied. On the other hand, some of the data not related to the action of the components used in carrier solution, demonstrated dose-dependent variation: found increased activity on 21-35% in the CYP2B1 at doses of 1 mg/kg and 10 mg/kg body weight, and reduced concentration of uric acid and increasing concentrations of urea at 10 mg/kg body weight. Nevertheless, these changes were within the physiological range of variability. However, it is worth noting an important significant (p = 0.02) increase of the absorption for antigenic proteins in the digestive tract in animals treated with fullerene C60 at a dose of 10 mg/kg, suggesting a marked effect on the intestinal wall.

[Toxicological and sanitary characterization of bentonite nanoclay].

Intragastric administration of nanoclay to rats during 28 days led to reductions in the relative weight of the liver, the activity of its conjugating enzymes, the antagonistic activity of bifidoflora, and the hyperproduction of colonic yeast microflora. The findings lead to the conclusion that nanoclays that may be present in foods must be the object of sanitary regulation.

[Toxicological and sanitary characteristics of fullerene C60 administered to the rat gastrointestinal tract].

A four-week experiment dealing with the intragastric administration of fullerene C60 dispersion to rats has established that this substance in a dose of 1 to 10 mg/kg body weight causes a number of changes in the parameters of animals, such as reductions in relative liver weight and isoform CYP 1A2 activity and increases in glutathione reductase activity, eosinophils, and neutrophils. It is concluded that fullerene can affect the animals when orally given in the doses studied.

[Effects of green tea extract and its components on antioxidant status and activities of xenobiotic metabolizing enzymes of rats].

Dietary administration of green tea extract (GTE) or epigallocatechin gallate (EGCG), quercetin (Qu) or caffeine (Cf) in doses equal to their concentration in GTE led to an increase of serum and liver antioxidant capacity and strengthening stability of microsomal and lysosomal membranes in rats. The antioxidant efficiency of EGCG and Qu was considerably higher than that of GTE. There were significant differences in the effects of EGCG, Qu and GTE on the activities and expression of mRNA for CYP1A1, CYP1A2 and CYP3A1. But feeding both GTE and Cf to rats results in similar elevated activities of CYP1A1, CYP1A2, UDP-glucuronosyl transferase and glutathion transferase. Our results suggest that Cf is the main contributor to GTE effects on activities of xenobiotic metabolizing enzymes.

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 ethoxyresorufin dealkylase (EROD), methoxyresorufin dealkylase (MROD), pentoxyresorufin dealkylase (PROD), and 6ß-testosterone hydroxylase (6ß-TH) and the content of mRNA for CYP1A1, CYP1A2, and CYP3A1 were elevated in the liver of 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 6ß-TH, and expression of the corresponding genes. Combined treatment was characterized by potentiation of the antioxidant effects of these compounds.

[Medical and biological safety assessment of genetically modified soybean event MON 89788. Report 1. Toxicologo-hygienic examinations].

The results of toxicologo-hygienic examinations, which were conducted within the framework of integrated medical and biological assessment of genetically modified second generation soybean event MON 89788, are presented. Analysis of morphological, hematological, biochemical parameters and system (sensitive) biomarkers has not confirmed any toxic effect of soybean event MON 89788.

[Toxicological and hygiene characterization of titanium dioxide nanoparticles introduced to the gastrointestinal tract of rats. Communication 1. Integral, biochemical and hematologic indices, small intestinal macromolecule absorption, DNA damage].

Water suspensions of titanium dioxide nanoparticles were introduced intragastrically to growing male Wistar rats daily for 28 days. The data obtained revealed the presence of toxic risks related to said nanomaterials action and demonstrate the necessity of sanitary regulation of titanium dioxide nanoparticles used in food contact materials, cosmetics and other commodity.

[Medical and biological safety assessment of genetically modified maize strain MIR604].

The results of toxicologo-hygienic examinations, which were conducted within the framework of integrated medical and biological assessment of genetically modified rootworm Diabrotica spp.-protected maize event MIR604, are presented. Analysis of morphological, hematological, biochemical parameters and system (sensitive) biomarkers has not confirmed any toxic effect of maize event MIR604.

[Medical and biological safety assessment of genetically modified maize event MON 88017. Report 1. Toxicologo-hygienic examinations].

The results of toxicologo-hygienic examinations, which were conducted within the framework of integrated medical and biological assessment of genetically modified rootworm Diabrotica spp.--protected and glyphosate tolerant maize event MON 88017, are presented. Analysis of morphological, hematological, biochemical parameters and system (sensitive) biomarkers has not confirmed any toxic effect of maize event MON 88017.

[Effect of T-2 toxin on organ ultrastructure and organelle-specific enzyme activity in rats]. / Vliianie T-2 toksina na ul'trastrukturu i aktivnost' organello-spetsificheskikh fermentov nekotorykh organov krys.

The time-course of the ultrastructural changes and activities of 6 marker enzymes of subcellular particles (succinate dehydrogenase, beta-glucosidase, beta-N-acetylglucosaminidase, acid RNAse, glucose-6-phosphatase and 5'-nucleotidase) has been studied in the liver, spleen and thymus in rats administered T-2 toxin (mycotoxin produced by some Fusarium species). A pronounced difference in the effect of T-2 toxin on the organs has been found. In the liver, the toxin induced a destruction of rough endoplasmic reticulum membranes, reduced ribosome number and progressively decreased activities of most enzymes. In the spleen, early and significant ultrastructural disturbances of all the cell membrane components and simultaneous lysosomal activation were observed. The changes in the thymus were characterized by a fast development of cell hydratation, organelle swelling and necrosis of some thymocytes with parallel increase in repair processes, infiltration by phagocytes and a selective activation of lysosomal hydrolases in the end of experimental time (72 h.). The results obtained emphasize an importance of cellular and subcellular membrane alterations in the mechanism of T-2 toxin action.

[Effect of T-2 toxin on the activity of organelle-specific enzymes of various rat organs]. / Deistvie T-2 toksina na aktivnost' organellospetsificheskikh fermentov razlichnykh organov krys.

Dynamics of 5 marker enzymes activity from subcellular particles--succinate dehydrogenase, beta-glucosidase, arylsulphatases A and B, acid RNAase and glucose-6-phosphatase--were studied in liver, spleen, thymus and blood serum of rats after single intragastric administration of T-2 toxin at a dose of 3.8 mg/kg (LD50). The acute intoxication was accompanied by an early (within 1-3 hrs) and significant reduction of total proteins in the tissues studied. Distinct tissue- and organelle-tropic effects of T-2 toxin were found: the toxin induced a gradual decrease in activity of the enzymes studied in liver tissue, while selective activation of lysosomal hydrolases was observed in spleen and thymus tissues. The selective effect of T-2 toxin on spleen and thymus lysosomal hydrolases appear to be involved in the mechanism of action of the toxin.

[Effect of vitamin A excess and T-2 toxin on the enzyme system activities of the second phase of xenobiotic metabolism in the rat liver]. / Vliianie izbytka vitamina A i T-2 toksina na aktivnost' fermentnykh sistem vtoroi fazy metabolizma ksenobiotikov v pecheni krys.

Oral administration of retinyl palmitate to young Wistar rats during 7 days (70,000 IU of vitamin A per 100 g of body weight daily) caused a decrease in the liver UDP-glucuronosyl transferase and glutathione transferase activities and a significant decrease in the liver glutathione-SH content. A single administration of T-2 toxin (3 mg per kg of body weight) to rats after the treatment with high doses of vitamin A was accompanied by an increase in T-2 toxicity. The rat mortality was doubled and the decrease in UDP-glucuronosyl transferase and glutathione transferase activities was more distinct as compared with the rats treated with T-2 toxin only. Vitamin A excess appears to decrease the phase II drug-metabolizing enzyme activities and glutathione-SH content in rat liver tissue. Excess of vitamin A may be responsible for an increase of T-2 toxicity in rats.

[The effect of selenium on enzymes metabolizing xenobiotics in rat liver]. / Vliianie selena na fermenty metabolizma ksenobiotikov pecheni krys.

Activity of enzymes involved in metabolism of xenobiotics was not altered in liver tissue of rats kept on a ration enriched with selenium at a dose of 2.5 mg/kg. Both organic form of selenium (yeast meal, selenomethionine) and inorganic derivatives (sodium selenite) at a dose of 5 mg/kg of ration caused distinct activation of epoxide hydrolase, UDP-glucuronosyl transferase and glutathione transferase within 6 weeks after the experiment beginning, while content of cytochrome P-450, glutathione-SH and glutathione peroxidase activity were not significantly altered. Within 9 weeks the enzymatic activity remained at the higher rate only in rats kept on the ration with sodium selenite. Relationship between toxic effects of selenium high doses and alterations in activity of enzymes involved in metabolism of xenobiotics is discussed.