International Journal Bioautomation (Sep 2014)
Pathological Study of the Lung of Rabbits Exposed to Suspension of Different Crystalline Nano-titanium Dioxide
Abstract
Objective. To compare the pathology changes of rabbit lung tissue contaminated by nano and micro TiO2 suspension liquid in different crystal forms. Methods. Each rabbit according to 2.5 ml·kg-1·bw-1 dose, one-time non-exposed pipe drip dye, and put them to death after 21 days. Lung was taken with paraffin embedding, tissue section and hematoxylin and eosin (HE) staining for observation. Results. In anatase TiO2 nanoparticles group, white single lung nodules could be seen on the surface of the lung. Microscopically, in the center of the nodules, the high density inflammatory lesion is given priority to lymphocytes aggregation. In macrophages, anatase TiO2 nanoparticles were shown brown and granule, which were deposited in pulmonary interstitial. Alveolar septum was widening with edema of alveolar epithelial cells. In rutile TiO2 nanoparticles group, alveolar epithelial cell was swelling and fell off. Alveolar space was narrow, where a large number of nano rutile TiO2 macrophages and neutrophils infiltrations could be seen. Rutile TiO2 nanoparticles could also be seen deposited on the pulmonary interstitial in abundance. Alveolar septum was widening, with fibrosis of chronic inflammation cells and fibroblasts. No significant difference was between the micron rutile and anatase TiO2 groups, while the alveolar structures were clear, with narrow alveolar space, widen alveolar septum, visible fibrosis, angiotelectasis hyperemia, and inflammatory lesion with lymphocytic infiltration predominantly in small bronchial submucosa. Micro rutile and anatase TiO2 were deposited in pulmonary interstitial and devoured by macrophages. The macrophages with foreign body were in black. But no obvious pathological changes were seen in the control group. Conclusion: Both of the TiO2 could lead to the damage to alveolar structure at the experimental doses. For two kinds of crystal types, contamination with nano TiO2 was more serious than micron TiO2, while anatase TiO2 could result in pulmonary nodules.
