Impact of silica dioxide nanoparticles on the morphology of internal organs in rats by oral supplementation

The object of the study was amorphous silica dioxide (SiO2), which is widely used as a food additive (E551), a subsidiary component in pharmaceutical preparations, perfumery and cosmetic products etc. In the specification of JECFA silica dioxide does not have information about the size of its particles, which allows the use of fine amorphous SiO2, obtained by gas phase hydrolysis of tetrachlorosilane as a food additive. This material, known as the "Aerosil", is characterized by the size of the specific surface area of ​​300-380 m2/g and the size of its relatively weakly agglomerated particles of 6-30 nm, i.e., it is a nanomaterial. In the biological model the morphological changes in organs and tissue systems on oral supplementation of nanoscale particles of silica dioxide were studied. Wistar male rats were given nanosized silica dioxide with specific surface area of ​​300 m2/g and primary nanoparticle size on the basis of data of electrical, atomic-powered microscopy, and dynamic light scattering in the range of 20-60 nm during 92 days. Light microscopic morphological examination of organs of rats showed a relatively mild inflammation in the structure of parenchymal organs (liver, kidney), not showing a certain dose-dependent nanoparticles. The most pronounced changes were in ileum morphology, consisting of a massive lymph macrophage and eosinophil infiltration of villi, without any apparent violation of their epithelial layer structure, which indirectly indicates the absence of violations of the barrier function of the intestinal epithelium. At the maximum dose of 100 mg/kg bw, the increased immune response was the most significant in the wall of the ileum. The results indicate the potential risks to human health when using SiO2 having a specific surface area of ​​300 m2/g or higher in the composition of food products as a food additive.