Morphological Changes in Lung Tissues of Mice Caused by Exposure to Nano-Sized Particles of Nickel Oxide

Abstract

The authors detected nidal perivascular and peribronchial lymphoid infiltration with macrophages and eosinophils admixtures in lung tissues of BALB/C mice with body weight equal to 25–30 g after a single 4-h inhalation exposure to nickel oxide, the size of its particles being 17–40 nm, and the actual concentration of the compound being equal to 1.34 ± 0.07 mg/dm3. Such changes occurred only in the experimental group and nothing similar was detected either in mice from the comparative group that had been exposed to macrodisperse nickel oxide or in mice from the reference group. Changes in alveolar patterns were examined via fractal analysis of images; the examination results revealed that more apparent changes in fractal dimension occurred under exposure to nanoparticles of nickel oxide. Fractal dimension of the alveolar pattern in the lungs of mice from the experimental group was 7% higher than in the reference group, and 4% higher than in the comparative group. Fractal dimension was the highest for those parts of the lungs where lymphoid infiltration occurred; it was 11% higher than the same parameter in the reference group, and 7% higher than in the comparative group. The greatest number of alveolar elements with their sphericity coefficient being equal to 0.7–0.8 was observed in the reference group; this parameter decreased in both comparative and experimental groups, but in both groups there was an increase in a number of elements with sphericity coefficient being equal to 0.4–0.5, and there were even significantly deformed elements with the coefficient being equal to 0.2. The greatest dispersity factor value was detected in the reference group; the lowest dispersity factor value, in the experimental group. The changes the authors revealed in lung tissues prove that nano-sized nickel oxide particles are more toxic than those of micro-dispersed analogue.