[Toxicological assessment of nanostructured silica. II. Enzymatic, biochemical indices, state of antioxidative defence].

Nanostructured silica (SiO2) "Aerosil" with the size of the primary nanoparticles (NPs) of 5-30 nm, in the form of ultrasound treated water suspension was administered to rats of 80 ± 4 g initial body weight for the first 30 days by intragastric gavage and then for 62 days with diets consumed in doses of 0.1; 1.0; 10 and 100 mg/kg body weight per day.

[Effects of vitamins deficiency on the cytochrome P450 inducibility in rats].

The purpose of the study was to determine multi-vitamin deficiency effects on the inducibility of main isoforms of cytochrome P450 in the rat liver. The study was carried out on 4 groups of Wistar rats. Rats of the 1st and 3rd group received semi-synthetic diets containing adequate (100% of recommended vitamin level) level of vitamins, the 2nd and 4th--the semi-synthetic diet containing vitamins in the amount of 20% from adequate level.

[Effects of polyvitamin deficiency on the activity of xenobiotic-metabolizing enzymes in rat liver].

The activity of xenobiotic-metabolizing enzymes was studied in the liver of male Wistar rats, which were fed for 4 weeks diets, containing 100 (control), 50 and 20% of vitamin adequate level. Moderate (50%) polyvitamin deficiency increased activity of EROD (by 13%), MROD (by 34%; p<0,05), 4-nitrophenol hydroxylase (by 16%), 6beta-testosterone hydroxylase (by 17%), UDP-glucuronosyle transferase (by 26%, p<0,05) and quinone reductase (by 55%, p<0,05). Deep (20%) polyvitamin deficiency decreased in liver activity of MROD (to 78% of control level, p<0,05), 4-nitrophenol hydroxylase (to 74%, p<0,05), heme oxygenase-1 (to 83%, p<0,05) and quinone reductase (to 60%, p<0,05).

[Comparative evaluation of antioxidant activity of phycocyanin and selenium enriched phycocyanin in vitro and ex vivo].

Antioxidant properties of phycocyanin and selenium enriched phycocyanin were evaluated by using FRAP assay, inhibition of luminol oxidation in Hb - H2O2 system and inhibition of induced microsomal lipid peroxidation. In different model systems phycocyanin revealed antioxidant activity wich was comparable with antioxidant activity of bilirubin and Trolox. Inclusion of selenium into phycocyanin did not influence significantly its antioxidant properties.

[Effect of protein deficiency and antigenic stimulation on rat liver lysosomes].

The total and non-sedimentable activities of liver beta-galactosidase, beta-glucoronidase, beta-N-acetyl glucosaminidase, aryl sulfatases A and B were studied during antigenic stimulation of rats fed balanced and low-protein (5% of energy value) diets. Antigenic stimulation of rats fed a balanced diet was found to intensify the total activities of all lysosomal enzymes (up to 124-246% of control). Meanwhile protein deficiency did not cause any significant reduction in immune response and completely removed activation of lysosomal hydrolases.