Some peculiarities of pulmonary clearance mechanisms in rats after intratracheal instillation of magnetite (Fe3O4) suspensions with different particle sizes in the nanometer and micrometer ranges: are we defenseless against nanoparticles?

We studied differences between phagocytic responses to nanoparticles (NPs) versus microparticles in the pulmonary region by synthesizing magnetite of different sizes and instilling suspensions of these particles intratracheally into rats' lungs. Ten and 50 nm particles caused a greater increase in cell counts of the bronchoalveolar lavage fluid (BALF) than the instillation of microparticles. The response to 10 nm particles was weaker than to 50 nm ones, and the smaller NPs were more cytotoxic; both were more cytotoxic than the microparticles.