Ultrastructural changes in the air-blood barrier in mice after intratracheal instillations of Asian sand dust and gold nanoparticles

The purpose of this study was to investigate a possible translocation pathway of intratracheally instilled gold nanoparticles after the induction of acute pulmonary injury by Asian sand dust. ICR mice were intratracheally instilled with 800 μg Asian sand particles (CJ-2 particles) 24 h before instillation of 50-nm gold nanoparticles. Lungs from mice treated with Asian sand particles and gold nanoparticles showed an acute focal inflammation with an increased expression of proinflammatory cytokines (IL-6 and TNF-α) and oxidative stress markers (Cu/Zn SOD and iNOS) in alveolar macrophages, type I alveolar epithelial cells, and endothelial cells at the alveolar walls. Electron microscopy revealed a destruction of the alveolar walls with an increased number of endocytic vesicles in the cytoplasm of both type I epithelial cells and endothelial cells; gold nanoparticles were demonstrated in these endocytic vesicles. These findings suggest that translocation of the exposed nanoparticles may be enhanced in the lung tissues with acute inflammatory changes.