RESUMO
The aim of our investigation was to make a comparative assessment of the biological effects of silver nanoparticles encapsulated in a natural and synthetic polymer matrix. We carried out a comparative assessment of the biological effect of silver nanocomposites on natural (arabinogalactan) and synthetic (poly-1-vinyl-1,2,4-triazole) matrices. We used 144 three-month-old white outbred male rats, which were divided into six groups. Substances were administered orally for 9 days at a dose 500 µg/kg. Twelve rats from each group were withdrawn from the experiment immediately after nine days of exposure (early period), and the remaining 12 rats were withdrawn from the experiment 6 months after the end of the nine-day exposure (long-term period). We investigated the parietal-temporal area of the cerebral cortex using histological (morphological assessments of nervous tissue), electron microscopic (calculation of mitochondrial areas and assessment of the quality of the cell nucleus), and immunohistochemical methods (study of the expression of proteins regulating apoptosis bcl-2 and caspase 3). We found that the effect of the nanocomposite on the arabinogalactan matrix causes a disturbance in the nervous tissue structure, an increase in the area of mitochondria, a disturbance of the structure of nerve cells, and activation of the process of apoptosis.