Impact of palladium nanoparticles (Pd-NPs) on the biology of neutrophils in vitro and on leukocyte attraction in vivo

Abstract

Recently, palladium nanoparticles (Pd-NPs) have been shown to possess pro-inflammatory activities. Herein, we investigated potential in vitro effects of Pd-NPs (primary size of 1–10 nm) on the biology of neutrophils, key player cells in inflammation. Also, the aim of this study was to evaluate the pro-inflammatory activity of Pd-NPs using the murine air pouch model, a model previously proposed to be used as a standard assay for testing in vivo pro-inflammatory effects of NPs. Although the positive controls used in vitro give the expected results in all biological functions tested, Pd-NPs do not affect the production of reactive oxygen species and that of interleukin-1β (IL-1β), IL-6, and IL-8. Pd-NPs moderately increase cellular adhesion of neutrophils onto human endothelial cells and significantly increase the capacity of neutrophils to migrate and to delay apoptosis. We conclude that Pd-NPs possess some pro-inflammatory activity in vitro but do not attract leukocytes in vivo regardless of sex.