The article presents results of histologic and immunohistochemical examination of nerve tissue of outbred white rats subjected over 9 days to nanobiocomposite containing nanoparticles of silver and natural biopolymer arabinogalactane. Exposure to the studied chemical was proved to cause structural and functional changes in nervous tissue. Comparing results of structural study of nervous tissue with expression of proteins caspase-3 and bcl-2 proves ability of nanosilver incapsulated into polymer matrix to penetrate through blood-brain barrier and induce apoptosis in neurons of brain cortex.