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.

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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.

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Background: Titanium dioxide (TiO2) is currently one of the most widely known nanomaterials produced for different purposes. The adverse effects of nano-dispersed TiO2 cause a serious concern about human health problems related to the intake of TiO2 nanoparticles (TiO2 NPs). The investigation of TiO2 NPs’ penetration through the gut epithelium into secondary organs and the relevant biological effects has an undoubted importance when assessing the potential risk of using TiO2 NPs. Objective: In the current study, we investigated the effect of rutile TiO2 NPs on tissues of the small intestine, liver, and spleen. For this purpose, we used a physiological model that simulates the single administration of TiO2 NPs directly into the intestinal lumen of an experimental animal. Methods: Suspensions TiO2 NPs were administered via an isolated loop of the small intestine at a single dose of 250 mg/kg of body weight. TiO2 NPs were detected in rats’ tissues by transmission electron microscopy. Results: TiO2 NPs were found in tissues of the small intestine mucosa, liver, and spleen. The administration of TiO2 NPs resulted in different changes in the cellular ultrastructures: hyperplasia of the smooth endoplasmic reticulum, an increase in the size of the mitochondria, the emergence of local extensions into the perinuclear space, and the appearance of myelin-like structures. Conclusion: The ultrastructural changes found in the individual cells of the small intestine, liver, and spleen indicated intracellular pathology, induced by the high doses of the TiO2 NPs. The spleen tissue appeared to be the most sensitive to the effect of TiO2 NPs.