The Effect of Magnetite Nanoparticles and Bacteria on the Activity of NADPH-Oxidase and Myeloperoxidase in Neutrophils of Human Blood

Abstract

Differences in the oxygen-dependent reactions of neutrophil granulocytes (NGs) depending on the nature of the agent affecting the cells were revealed. In vitro magnetite nanoparticles (MNPs) cause suppression of the NADPH–oxidase activity of NGs, which manifests itself in falling rates of reactions (NBT test) both with the effect of MNPs on NGs alone and a combined effect (MNPs and zymosan), as well as in the reduction of the index of activation (IA) and functional reserve of neutrophils (FRN). However, the introduction of MNPs dose-dependently stimulates the activity of myeloperoxidase (MPO). Gram-positive (S. aureus 2879 M) and gram-negative (E. coli 321) bacteria caused a respiratory burst of neutrophils, which manifested itself in a significant increase in the number of NBT-positive cells in single and combined influences (bacteria and zymosan). The lack of differences in the reaction of cells on opsonized and nonopsonized bacteria and the decrease in IA and FRN suggest that NGs are at the maximum level of functionality. Both strains of bacteria caused activation of the MPO.