Structural basis of the pathogenic effect of ultramicroscopic particles of titanium nitride on the respiratory system

Abstract

Interest to nanodispersive materials is connected with their common use in industry as a primary raw material. There is a likelihood of areal dust output hazard in the air of the working place. That’s why a histological study of the lungs in the experimental animals was an urgent one. Objective. We studied the effect of the ultramicroscopic nitride titanium dust factor on the laboratory rats’ respiratory organs by means of the intratracheal introduction. Materials and мethods.The study was conducted in 18 white rats of the same weight. Ultramicroscopic titanium nitride was intratracheally administered to the animals. The lung slices were prepared using a microtome for histological examination. We stained the sections with hematoxylin and eosin by Van Gieson method and evaluated them with the help of microscope. Results. We established previously that operators of thermosynthesis had been exposed to titanium nitride.The amount of dust nanoparticles was determined in the samples, their mass concentration per cubic meter and total surface area made up 5.35 g/m3 and 1.33Ч108 nm2/cm3. Conglomerates of titanium nitride powder were identified in the macrophages among the alveolar membranes in the form of either larger or smaller clusters with its decrease in the dynamics of the experiment. Intraalveolar membranes were thickened in the areas of material accumulation, infiltrated mainly by small and medium lymphocytes with plasmocites, tissue basophils, macrophages, and occasionally neutrophilus. The ultramicroscopic titanium nitride administration resulted in the morphological signs of chronic bronchitis onset: thickening, swelling and infiltration of all walls’ layers, and dystrophic changes and desquamations of ciliated epithelium as well. Conclusions: A single intratracheal titanium nitride ultramicroscopic particles’ administration causes the structural changes in the bronchial tree and respiratory segment, their severity and character depend on the aerosol exposure duration.