This paper provides a comprehensive summary of the main toxicological studies conducted on selenium nanoparticles (NPs) using laboratory animals, up until February 28, 2023. A literature search revealed 17 articles describing experimental studies conducted on warm‐blooded animals. Despite some uncertainties, in vivo studies have demonstrated that selenium NPs have an adverse effect on laboratory animals, as evidenced by several indicators of general toxic action. These effects include reductions of body mass, changes in hepatotoxicity indices (increased enzyme activity and accumulation of selenium in the liver), and the possibility of impairment of fatty acid, protein, lipid, and carbohydrate metabolisms. However, no specific toxic action attributable solely to selenium has been identified. The LOAEL and NOAEL values are contradictory. The NOAEL was 0.22 mg/kg body weight per day for males and 0.33 mg/kg body weight per day for females, while the LOAEL was assumed to be a dose of 0.05 mg/kg of nanoselenium. This LOAEL value is much higher for rats than for humans. The relationship between the adverse effects of selenium NPs and exposure dose is controversial and presents a wide typological diversity. Further research is needed to clarify the absorption, metabolism, and long‐term toxicity of selenium NPs, which is critical to improving the risk assessment of these compounds.

Diversity of secondary lichen metabolites was studied in epiphytic lichens on six phorophytes—spruce, pine, birch, alder, aspen and poplar in the Middle Urals of Russia. Atranorin, usnic, fumarprotocetraric acid, zeorin, and gyrophoric acid were found in 31, 24, 23, 18, and 14 species, respectively, of 237 taxa collected. Seventy-seven species (i.e., 32% of total species documented) contained no secondary metabolites. Spectra of secondary metabolites of fruticose and foliose lichens varied on different phorophytes, while in crustose species the strong dependence on the tree species was not detected. This is different to the pH dependence of saxicolous lichens where crustose lichens were more susceptible to the rock chemistry. The results of Canonical Correspondence Analysis reveal the affinity of species containing depsides, depsidones or usnic acid to acidic substrata and those lacking secondary metabolites or containing terpenes and antraquinones to the pH-neutral bark. We suppose that phenolic compounds and flavonoids, as chemical constituents of bark, may interact with lichen symbioses and elements in phellem, and similarly to the lichen acids shape the affinity of species to the substrata.

Industrial production generates aerosols of complex composition, including an ultrafine fraction. This is typical for mining and metallurgical industries, welding processes, and the production and recycling of electronics, batteries, etc. Since nano-sized particles are the most dangerous component of inhaled air, in this study we aimed to establish the impact of the chemical nature and dose of nanoparticles on their cytotoxicity. Suspensions of CuO, PbO, CdO, Fe2O3, NiO, SiO2, Mn3O4, and SeO nanoparticles were obtained by laser ablation. The experiments were conducted on outbred female albino rats. We carried out four series of a single intratracheal instillation of nanoparticles of different chemical natures at doses ranging from 0.2 to 0.5 mg per animal. Bronchoalveolar lavage was taken 24 h after the injection to assess its cytological and biochemical parameters. At a dose of 0.5 mg per animal, cytotoxicity in the series of nanoparticles changed as follows (in decreasing order): CuO NPs > PbO NPs > CdO NPs > NiO NPs > SiO2 NPs > Fe2O3 NPs. At a lower dose of 0.25 mg per animal, we observed a different pattern of cytotoxicity of the element oxides under study: NiO NPs > Mn3O4 NPs > CuO NPs > SeO NPs. We established that the cytotoxicity increased non-linearly with the increase in the dose of nanoparticles of the same chemical element (from 0 to 0.5 mg per animal). An increase in the levels of intracellular enzymes (amylase, AST, ALT, LDH) in the supernatant of the bronchoalveolar lavage fluid indicated a cytotoxic effect of nanoparticles. Thus, alterations in the cytological parameters of the bronchoalveolar lavage and the biochemical characteristics of the supernatant can be used to predict the danger of new nanomaterials based on their comparative assessment with the available tested samples of nanoparticles.

Introduction. Ubiquity of nanoparticles (NPs) necessitates the increase in the resistance and tolerance of the human body to their toxic effects. The exposure to nanoparticles can occur not only in the occupational setting but also because of environmental pollution and a purposeful use of nanomaterials (e.g., in medicine and cosmetology). Impossibility of elimination of nanoparticle exposure and its adverse health effects at the current stage of technological development makes the problem even more urgent. Our objective was to study the ability of bioactive agents (vitamins, macro- and microelements, flavonoids, etc.) to enhance the defense response to nanoparticle toxicity. Material and methods. The analysis and generalization of modern scientific research is carried out. To review and summarize data of recent scientific studies, we have done a literature search using PubMed, Web of Science, and Google Scholar search engines, as well as Russian scientific electronic libraries eLibrary.ru and Cyberleninka.ru. The inclusion criteria were information about adverse health effects of nano-sized particles (1–100 nm) and attenuation of their toxicity using bioprotectors in experimental animals. After primary screening of more than 70 publications, we selected thirty-six articles for the review. Results. The ability of bioactive agents to increase the resistance of a living organism, including warm-blooded mammals, to nanoparticle exposure has been demonstrated. We established a protective effect of vitamin E against nephrotoxicity of gold NPs and toxicity of silver NPs; vitamin C against the hepatotoxic effect of titanium (IV) oxide NPs and reproductive toxicity of nickel NPs, and B vitamins against toxic effects of zinc oxide NPs. We have also found evidence of a protective effect of selenium against silver NPs, including cardioprotective ones. Flavonoids (hesperidin and quercetin) demonstrated protective effects against nephro-, neuro- and hepatotoxicity of nanoparticles. In addition, we noted their positive role in repair of mitochondrial dysfunction. L-arginine also showed the ability to attenuate poisoning induced by Au NPs. Limitations of the study. We reviewed open access Russian and English-language publications. Conclusion. This literature review facilitates identification of the most effective ways to increase the resistance and tolerance of a living organism to adverse health effects of nanoparticles.