[Changes in proteome profiles of rat liver microsomes induced by silicon dioxide nanoparticles].

The effect of daily intragastric administration of an aqueous dispersion of silicon nanoparticles (NPs) (the dose range from 1.0 mg/kg to 100 mg/kg body weight for 28 days) to rats on the proteomic profile of liver microsomes has been investigated by 2D-electrophoresis followed by subsequent mass spectrometry identification. The liver microsomal fraction was isolated by differential centrifugation and its protein composition was analyzed by 2D-polyacrylamide gel electrophoresis. Identification of protein spots was carried out using MALDI-TOF mass spectrometric analysis. The mass spectrometry analysis revealed the protein GRP78 (78 kD glucose-regulated protein precursor), belonging to the family of heat shock proteins. This protein present in animals of the control group was not detected in NP-treated rats of group 2 (1 mg/kg body weight/day) and group 3 (10 mg/kg body weight/day). This protein predominantly localized in the liver cell endoplasmic reticulum and plasma membrane has the chaperone biological activity. Possible mechanisms of the effects of engineered nanoparticles on biosynthetic processes in the body are discussed.

[Toxicological assessment of nanostructured silica. I. Integral indices, adducts of DNA, tissue thiols and apoptosis in liver].

Nanostructured amorphous silica (SiO2) is widely used in food additives, pharmaceuticals and cosmetics. Available data on the oral toxicity of this nanomaterial (NM) in vivo, obtained in acute and subacute experiments are contradictory. The purpose of this study is evaluation of some parameters of toxicity of nanostructured SiO2 when orally administered to rats for 3 months. We used commercial SiO2 preparation, obtained by gas-phase hydrolysis of tetrachlorosilane with a size of the primary nanoparticles close to 5-30 nm, which was characterized as NM by several independent methods. SiO2 in the form of sonicated aqueous dispersion was administered to male rats with initial weight of 80 +/- 4 g for the first 30 days by intragastric gavage and then for 62 days with consumed diets in daily dose of 0,1; 1,0; 10 and 100 mg/kg body weight. The control animals received vehicle--deionized water. Weight gain, relative mass of internal organs, intestinal permeability to protein macromolecules (determination of ovalbumin level in blood serum by solid-phase bivalent immunoassay), urinary excretion of oxidative degradation product of DNA 8-oxo-2-deoxyguanosine (8-oxo-G) (by reversed phase HPLC), the level of thiol compounds in liver (spectrophotometrically), liver cell apoptosis (flow cytometer), fixing efficiency of passive avoidance (CRPA) have been measured. It has been shown that three-month administration of nanostructured SiO2 in all doses resulted in animal body weight decrease by 10-15%; a significant increase in adrenal weight was noticed under doses of 1 and 10 mg/kg and urinary 8-oxo-G excretion was significantly reduced at the dose 10 mg/kg. At the maximum dose of NM, 100 mg/kg, after 2 months of administration the number of animals decreased that entered the dark compartment of the experimental setup at initial testing of CRPA. The rest of the studied indices did not experience any significant changes depending on the dose of NM. It is concluded that no toxic effect were expressed in indices studied under the influence of nanostructured SiO2 in rats at daily doses up to 100 mg per kg body weight for 3 months.

[Determination of major metal cations in juices and nectars by capillary zone electrophoresis].

The method of determination of potassium, sodium, calcium and magnesium cations by capillary zone electrophoresis (using lithium cations as the internal standard) in the juices and nectars was advised. Optimal conditions for electrophoretic separation: pH value of the working buffer (pH 3.6), the concentration of imidazole (contrast agent 15-20 mmol/dm3), the concentration of 18-crown-6 ether (2 mmol/dm3). The method was tested on 15 samples of juices and nectars. The results of determination of potassium and magnesium cations were compared with results obtained by mass spectrometry with inductively coupled plasma. The equation of the linear regression and R-squared value for determinations of magnesium cations were defined as: y = 0.999x + 3.29; R = 0.952; for determination of potassium cations: y = 0.959x + 51.94; R = 0.997; indicating good the correlation between the data obtained by these methods.

[Bioaccumulation of silver and gold nanoparticles in organs and tissues of rats by neutron activation analysis].

Bioaccumulation of silver (Ag) and gold (Au) nanoparticles (NPs) with mean sizes of 6 nm and 35 nm, respectively, has been studied after their intragastric administration to rats at a dose of 100 µg/kg of body weight for 28 or 14 days. The organs and tissues (liver, kidney, spleen, heart, gonads brain, and blood) were subjected to thermal neutron activation, and, then, the activity of the 110mAg and 198Au isotopes generated was measured. The NPs of both metals were detected in all biological samples studied, the highest specific weight and content of Ag NP being found in the liver, and those of Au being found in kidneys of animals. The content of Ag NPs detected in the brain was 66.4 ± 5.6 ng (36 ng/g tissue), no more than 7% ofthese NPs being localized in the lumen of brain blood vessels. The content of Ag and Au NPs found in organs and tissues of rats could be regarded as nonhazardous (nontoxic) in accordance with the known literature data.

Identification of silver nanoparticles in the small intestinal mucosa, liver, and spleen of rats by transmission electron microscopy.

The effects of water-dispersed Ag nanoparticles on the small intestinal mucosa, liver, and spleen of rats were studied by transmission electron microscopy. Acute experiments demonstrated penetration of Ag nanoparticles injected into the isolated intestinal loop into the intestinal mucosa, liver, and splenic tissues. Ultrastructural changes (lobed nucleus, megamitochondria) were found in the studied organs. These data indicated that injection of water-dispersed Ag nanoparticles into the gastrointestinal tract was followed by their penetration through the epithelium of the small intestinal mucosa into other organs, e.g. into the liver and spleen. This fact is essential for evaluation of potential risks of the nanoparticle effects on human health and environment.

[Determination of chondroitin sulfate in food supplements by capillary zone electrophoresis].

Chondroitin sulfate is widely used as an ingredient in food supplements. A method of capillary zone electrophoresis for qualitative and quantitative analysis of chondroitin sulfate in food supplements has been developed. The system of capillary electrophoresis Agilent 3D CE (USA) with diode array detector (spectral range 190-400 nm, 192 nm was used to quantity), quartz capillary Agilent with effective length 56 cm (USA) (internal diameter 50 microm, temperature 25 degrees C, 30 kV, negative polarity) and 50 mM phosphate buffer (pH 3.5) has been used. Quantity limit of this method was 0.5 g/kg. It was used for determination of content of chondroitin sulfate in 14 food supplements. The chondroitin sulfate was detected in all test samples with deviation from the declared content (25-600 mg per capsule or tablet) at the level of 1 to 9%. The applicability of the elaborated method for assessing of food supplements quality has been shown.

[Hematologic indices in different age wistar rats, receiving a balanced semi-synthetic vivary diet].

This paper presents the results of research of hematologic parameters of male Wistar rats 1, 2, 3, 4 and 6 months age, which received a balanced semisynthetic diet. Studies were carried out at the Hematology analyzer Coulter AC TTM 5 diff OV (Beckman Coulter, USA) with the program, specially developed for the study of rats' blood. According to the results of research, was found a statistically significant increased of the number of red blood cells; the concentration of hemoglobin and hematocrit in animals 2-6 months compared with rats, 1 month age. With age, there is a decrease of the mean corpuscular volume and the mean corpuscular hemoglobin. The number of white blood cells in rats of 2-4 months age are significantly higher than in rats of 1 and 6 months age. The number of neutrophils and eosinophils in rats of to the 2 month are of is lover than once in rats of 1 month age, and increases values in animals of 6 months age. The number of lymphocytes has the highest value in the rat of 2-3 months age and the minimum value is that in animals of 6 months age. With increasing of the age of the animals the reduction of contents of monocytes was noted. The content of platelets and the platelet crit in the blood of rats 6 months age is statistically greater than those in 1-month age animals. The average volume of platelet is the stable index, with age does not change.

[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.

[Effect of titanium dioxide nanoparticles on protein expression profiles in rat liver microsomes].

There was studied an influence of intragastric administration of titanium dioxide (anatase form) nanoparticles (NP) on protein expression profiles in rat's liver microsomes by methods of proteomics. Animals received water suspension of NP in doses from 0,1 to 10 mg per kg body weight intragastrically daily during 28 days. Microsomes were isolated from liver by means of preparative ultracentrifugation. Proteins composition was studied by 2D-electrophoresis in acrylamide gel. Protein spots were identified by MALDI-TOF analysis. The results demonstrated appearance of 53 new protein spots and disappearance of 19 spots in animals subjected to NP irrespective of their dose. In addition 25 new spots appeared and 3 disappeared in higher doses of NP when compared to low dose group and control animals. Mass-spectrum analysis showed presence of few polypeptides registered in international database among proteins expressed under influence of NP. One of this dominant expressed proteins corresponded to enzyme glutathione transpherase Mu 2 isoform (M=41,55 kD, pI=8,0). The conclusion was made of well advances of proteomic analysis in artificial NP influences on biosynthetic processes estimation.

[Studies of effects of aluminum oxide nanoparticles after intragastric administration].

Growing Wistar rats received intragastrically nanoparticles (NPs) of aluminum oxide (Al2O3) daily during 28 days at doses of 1 or 100 mg per kg body mass. There were studied body mass of animals, relative mass of internals, rate of protein macromolecules absorption in the gut, oxidative damage of DNA, pool of tissue thiols, activity of hepatic enzymes of xenobiotic detoxication system, biochemical and hematological blood indices, stability of lysosome membranes, condition of antioxidant defense system, apoptosis of hepatocytes. Conducted experiments didn't reveal any marked toxic action of Al2O3 NPs on rats after 28 days of administration both in high and low dose. Among effects probably related to NPs influence on animals there were lowering of relative liver and lung masses, decrease of hepatic thiol pool, activity of CYP1A1 isoform in liver and glutathione reductase in erythrocytes, increase of diene conjugates of fatty acids in blood plasma. Said shifts were small in magnitude, didn't come out of margins of physiological norm and didn't show any distinct relation to NPs dose. However considering great importance of this nanomaterial as probable environmental contaminant the studies of it's toxicity must be continued in conditions of low doses (less than 1 mg per kg body mass) for long period of time.

[Influence of dioxide titanium nanoparticles on immune system indicators in rats].

We investigated the possible influence of titanium dioxide TiO2 nanoparticles (NPs) (rutile form) on immunological parameters in rats. The experiment was carried out on 40 male Wistar rats, separated on 4 groups. Rats of 1 and 2 groups received intragastrically deionized water, 3 and 4 groups - aqueous dispersion of NPs in dose of 100 mg/kg body weight every day. Rats of 2 and 4 groups were immunized intraperitoneally with 100 mkg egg ovalbumin (OVA) on the 1st, 3rd and 5th days of the experiment. On day 21 was administered an additional 10 mkg OVA. In this study were assessed the concentration of specific IgG antibodies (humoral immune response), levels of IL-6, IL-10 and TNF-alpha, expression of lymphocyte antigens CD45RA, CD3, CD4, CD8, CD161alpha, phagocytic activity of neutrophils, lymphocyte apoptosis, hematology characteristics of blood. The studies showed that intra-gastric administration of rats with NPs in rutile form generates significant increase of humoral immune response against food antigen (p<0,05 according to the Student t-test). In the analysis of leukogram it was found a significant decrease of immature cells in immunized animals when exposed to NPs. Administration of NPs resulted in a significant decrease of the relative numbers of B-lymphocytes in immunized animals, and generated a significant increase in the phagocytic activity of peripheral blood neutrophils. Stimulation index of phagocytosis significantly increased at reception of NP by non-sensitized animals. Effects of NP rutile on levels of cytokine production (IL- 6, IL-10, TNF-alpha), on hematological characteristics of blood were insignificant both in intact and immunized animals. Thus, it is shown the intragastric administration of NP rutile has some influence on the specific and nonspecific unit of immune system in immunized and intact rats.

[Zero valent seleniume nanoparticles bioavailability estimation in rats].

Bioavailability of zero valent selenium (Se) nanoparticles with average size 60 nm was measured in rats receiving selenium deficient diet. There was demonstrated that intragastric administration of Se nanoparticles resulted in dose-dependent increase of serum Se level, normalization of tissue thiol pools, immune status and hepatocytes apoptosis. Possibilities are discussed of Se nanoparticles use in nutrition as a source of this trace element.

[Nanotechnology in food production: advances and problems].

Presented article is a review of the modern data on nanotechnology use in food manufacturing. There are discussed the basic scopes of nanotechnology application in food industry. One of the main problems arising in connection with introduction of nanotechnology in food, is an absence of reliable methods of identification and the control of nanoparticles is in structure of foodstuff including the control of their authenticity. Other problem is connected to necessity of an estimation of the risks connected to presence of potentially toxic nanoparticles in food. The analysis of foreign experience of researches in the given area allows to formulate methodological approaches to formation of domestic system of nanosafety.