Macrophages of the respiratory division of the lungs of rats after a single parenteral injection of silicon dioxide nanoparticles of various sizes

Abstract

The aim of the study was macrophages analysis of the respiratory tract in rats after a single parenteral administration of the silicon dioxide nanoparticles in a size of 7 nm and 34 nm during 6 months. Material and methods. The sections of the rat lung were studied using the methods of histology and immunohistochemistry after injection of 1 ml of 7 and 34 nm a SDNPs saline suspension at a concentration of 2 mg/ml (7mg/kg). Control animals were administered 1ml saline solution. To study chronic toxicity material sampling was performed on the 21st day, and 2, 4 and 6 months after the administration of the SDNPs (5 animals in the group) and fixed in 10% neutral formalin. Results. An increase in the number of interstitial and alveolar macrophages were identified by 4 months the introduction of silicon dioxide nanoparticles with a size of 7 nm, with normalization of the indicators by 6 months. The use of 34 nm nanoparticles does not cause significant changes of the respiratory tract of rats at all times of the experiment. Conclusion. A single parenteral administration of silica nanoparticles causes aseptic inflammation of the respiratory tract of rats and an increase in the number of alveolar macrophages by 4 months of the experiment only with the introduction of 7 nm silica nanoparticles. Both nanoparticle sizes don't cause tissue remodeling of the lung throughout the experiment.