Morphological Analysis of the Respiratory Tract of Rats after Parenteral Administration of Silicon Dioxide Nanoparticles.

Morphological analysis of the respiratory tract of Wistar rats was performed after a single parenteral administration of 12-nm silicon dioxide nanoparticles (1 ml, 2 mg/ml, intravenously) was performed. On day 21 and in 2, 4, and 6 months after the administration of nanoparticles, the development of macrophage infiltration in the interstitium of the respiratory tract was demonstrated by histological and immunohistochemical methods. The pool of alveolar macrophages increased in 4 months after administration (p=0.004) and returned to the control values in 6 months. The number of mast cells did not significantly change at all stages of the experiment. Connective tissue remodeling in the interstitium of the respiratory tract was not observed throughout the observation period.