[Physiological and biochemical studies as a necessary component of the algorithm for assessing the effectiveness of food minor biologically active substances].

Preclinical physiological and biochemical studies of the effectiveness of the tested biologically active substances in the conditions of simulated pathology in laboratory animals are an important stage preceding the assessment of the clinical effectiveness of the created specialized foods for therapeutic or preventive nutrition. The aim of this work is a brief review of the developed algorithm for preclinical assessment of the effectiveness of specialized foods, which includes a set of sequential stages of testing the safety, stability, bioavailability and effectiveness of biologically active substances in experiments on laboratory animals. Results. The paper presents a brief review of methodological approaches for in vivo preclinical assessment of the effectiveness of minor plant biologically active substances - polyphenols from bilberry fruits and leaves and phytoecdysteroids extracted from spinach. A beneficial effect of bilberry leaves' polyphenols on carbohydrate and lipid metabolism of male Zucker and Wistar rats was shown, which determined the necessity to increase the effectiveness of the developed polyphenolic ingredient by sorption on a food carrier. When evaluating the in vivo effects of polyphenols from blueberries and leaves sorbed on buckwheat flour, a pronounced hypoglycemic effect was found. The experiments aimed to the assessment of the adaptogenic effects of phytoecdysteroids from spinach leaves showed a significant decrease in the content of the main biomarkers of the stress system, which indicates a «smoothing¼ of the response of the animal organism to a strong stress impact. Conclusion. The inclusion of minor biologically active substances into the composition of foods for preventive and therapeutic nutrition is the necessary condition to improve their effectiveness. The scientific and practical significance of the preclinical evaluation to a decisive extent depends on the presence of a correctly selected biomodel. Thus, the adequacy of the assessment of the effects of minor biologically active substances as functional food ingredients in the composition of the specialized food products depends on the reproducibility of pathological processes (clinical, biochemical and morphological disorders) characteristic for the studied disease on the selected in vivo model.

Detection of Gold Nanoparticles in Rat Organs by Transmission Electron Microscopy.

The effects of water-dispersed gold nanoparticles (8.0±0.9 nm in diameter) on the rat small intestinal mucosa and Peyer plaques, liver, and spleen were studied by electron microscopy. Water-dispersed gold nanoparticles injected into isolated intestinal loop not only accumulated in the small intestinal mucosa and Peyer plaques, but also penetrated into other organs, e.g. liver and spleen. Ultrastructural changes in the cells (hyperplasia of endoplasmic reticulum) were detected in the studied organs.

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.

Effects of titanium dioxide nanoparticles on small intestinal mucosa in rats.

Penetration of titanium dioxide nanoparticles into enterocytes after their administration into isolated loop of rat small intestine was shown in vivo by transmission electron microscopy. Using electron diffraction, titanium dioxide nanoparticles were identified in the apical regions of the cells under plasma membranes and in deeper parts of the cytoplasm as solitary objects or small aggregations. Water dispersions of nanoparticles (3-h exposure to high concentrations) caused no appreciable morphological changes in enterocyte ultrastructure. A 28-day subacute intragastric administration of water dispersion of nanoparticles to rats led to titanium accumulation in the liver, their level was significantly higher than in the control group, which was shown by mass spectrometry with inductive-bound plasma. These data indicated the possibility of penetration of titanium dioxide nanoparticles through the gastrointestinal barrier under near-physiological conditions.