Silver nanoparticles (NPs), widely used in the manufacture of various types of consumer products and for medical applications, belong to novel types of materials that pose potential risks to human health. The potential negative effects of the influence of these NPs on reproduction are insufficiently researched. A quantitative assessment of the transfer of metallic silver nanoparticles through the placenta and breast milk was carried out during an in vivo experiment. We used 34.9 14.8 nm in size silver NPs that were stabilized by low-molecularweight polyvinylpyrrolidone and labeled with the 110mAg radioactive isotope using thermal neutron irradiation in a nuclear reactor. [110mAg]-labeled NPs preparations were administered intragastrically via a gavage needle to pregnant (20th day of gestation) or lactating (14-16th day of lactation) female rats at a dose of 1.69-2.21 mg/kg of body weight upon conversion into silver. The accumulation of NPs in rat fetuses and infant rats consuming their mothers breast milk was evaluated using a low-background semiconductor gamma-ray spectrometer 24 and 48 hours following labeling, respectively. In all cases, we observed a penetration of the [110mAg]-labeled NPs through the placenta and ther entry into the mothers milk in amounts exceeding by 100-1,000 times the sensitivity of the utilized analytical method. The average level of accumulation of NPs in fetuses was 0.085-0.147% of the administered dose, which was comparable to the accumulation of the label in the liver, blood, and muscle carcass of adult animals and exceeded the penetration of NPs across the hematoencephalic barrier into the brain of females by a factor of 10-100. In lactating females, the total accumulation of [110mAg]-labeled NPs into the milk exceeded 1.94 0.29% of the administered dose over a 48 h period of lactation; not less than 25% of this amount was absorbed into the gastrointestinal tract of infant rats. Thus, this was the first time experimental evidence of the transfer of NPs from mother to offspring through the placenta and breast milk was obtained.

Amino acids tyrosine (Tyr) and tryptophan (Trp) play a significant role in the regulation of energy metabolism, locomotor activity, and eating behavior. We studied the possibility of modulating these processes in obesity by increasing the pool of Tyr and Trp in the experimental diet. As a model of obesity, we used Wistar rats fed a diet with an excess specific energy value (HFCD) for 64 days. Trp led to a normalization of the rats’ body weight almost to the control level, but increased anxiety-like behavior and decreased long-term memory. The consumption of amino acids resulted in increased grip strength and impairment of short-term memory. The locomotor activity of animals decreased with age as a result of Tyr consumption, while Trp, on the contrary, prevented this. The Tyr supplementation led to the normalization of triglycerides and LDL. In the spleen cell lysates, amino acids suppressed the production of proinflammatory cytokines. The liver tissue morphology showed that the consumption of Tyr noticeably weakened the signs of fatty degeneration. The addition of Trp, on the contrary, led to an unfavorable effect, consisting of the appearance of a high number of large rounded fatty vacuoles. The data obtained indicate a more pronounced anti-inflammatory effect of Tyr as compared to Trp.

We compared anxiety, neuromotor, and cognitive functions in mutant rats with different allelic variants of dopamine transporter DAT knockout receiving balanced or excess in fat and fructose diet. The experiments were performed in DAT−/− homozygotes, DAT+/− heterozygotes, and DAT+/+ wild type rats. The genotype of DAT‐KO rats was confirmed by restriction analysis of DAT gene compared to behavioral responses in the open field test (OF). Animals in the first groups of each strain were fed a balanced AIN93M diet; and those in the second groups with a high‐fat/high‐fructose diet. Neuromotor function was studied as grip strength, and behavioral responses were assessed in the elevated plus maze and conditioned passive avoidance response tests. The mass of the internal organs and white and brown fat, as well as selected lipid and nitrogen metabolism parameters in blood plasma were determined at the end of the experiment. DAT−/− had the highest specific grip strength, and showed an increase in initial exploratory activity in comparison with DAT+/− and DAT +/+. The exploratory activity was significantly reduced in the second test compared to the first one in DAT−/− and DAT+/− of first but not second group. Anxiety decreased with age in the second groups of DAT+/− and DAT+/+ (but not in DAT−/−) and was higher in DAT+/+ than in DAT+/− and DAT−/−. Excess fat and fructose resulted in the deterioration of short‐term memory in DAT+/+. Lipidomic indices of blood plasma were less responsive to diet in DAT−/− and DAT−/+ in comparison to DAT+/+. The increased AsAT/AlAT activity ratio in DAT−/− compared with those in DAT+/+ suggests the activation of catabolism activity in the mutants. The consumption of excess fat and fructose significantly modified the effects produced by DAT gene allelic variants presumably due to the influence on the processes of dopamine metabolism.

The experimental data on the oral toxicity of nanostructured amorphous silica (SiO₂), widely used in food supplements, pharmaceuticals, and cosmetics, in terms of its in vivo effect on the immune system, are contradictory. Therefore, this study aimed to assess the rat’s immune function after SiO₂ oral administration. In the first experiment, SiO₂ was daily orally administered to Wistar rats for 92 days in doses of 0.1, 1.0, 10, and 100 mg/kg of body weight (bw). In the second 28-day experiment, SiO₂ in a dose of 100 mg/kg bw was daily orally administered to rats parenterally immunized with the food allergen ovalbumin (OVA) for the reproduction of systemic anaphylaxis reaction. Together with integral indices, we assessed intestinal permeability to protein macromolecules; hematology; CD45RA+, CD3+, CD4+, CD8+, and CD161a+ cells; cytokines TNF-α, IL-6, and IL-10; and IgG to OVA. The results obtained showed that SiO₂ has no effect on the severity of the anaphylactic reaction, but is capable inducing a toxic effect on the T-cell immune systems of rats. Estimated no observed adverse effect level NOAEL for SiO₂ ranges up to 100 mg/kg bw in terms of its daily consumption for 1–3 months. Using SiO₂ as a food additive should be the subject of regulation.

Bioaccumulation of silver (Ag) and gold (Au) nanoparticles (NPs) with mean sizes of 35 nm and 6 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% of these 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.