Assessment of Comparative Toxicity of Nano- and Microparticles Magnetite

The key mechanism of pulmonary region's clearance from deposited particles is recruitment of phagocytizing cells on its free surface. Phagocytosis hinders penetration of these particles into pulmonary interstices and thus promotes mucociliary clearancetil. The alveolar macrophage (AM) is the main cell effector of phagocytosis-mediated pulmonary clearance, the neutrophile leukocyte (NL) being the most important auxiliary one. NLs recruitment is controlled by the number of destroyed AMs. That's why the intensity of NLs recruitment toward deposited particles depends quantitatively on their cytotoxicity for macrophages([1-5]). Thus NL/AM ratio may be used as a criterion of comparative cytotoxicity of particles. Another nano-toxicological problem of theoretical and practical importance is the size-dependence of the comparative resorptive toxicity of particles of substances that are deemed innocuous in bulk.