The pulmonary effects and clearance of intratracheally instilled Ni3S2 and TiO2 in mice.

The effects and clearance of intratracheally instilled nickel subsulfide (Ni 3 S 2 ) and titanium dioxide (TiO 2 ) were compared. Instilled Ni 3 S 2 was acutely toxic to mice. Blood was recovered from the lungs during lavage, pulmonary polymorphonuclear leukocyte cell levels were increased, body weights decreased, and mice appeared clinically sick. These effects were in contrast to TiO 2 -instilled animals, which appeared similar to phosphate-buffered saline-in-stilled controls. The clearance of instilled particles from the lungs was examined for both Ni 3 S 2 - and TiO 2 -exposed mice. Particles were rapidly cleared to the gastrointestinal (GI) tract within 15 min; this clearance was nonspecific for Ni or Ti and appeared to be due to the coughing reflex. Significantly less Ni was present compared with TiO 2 in mouse lungs at 3 and 7 days postexposure ( P 63 Ni was first solubilized in the lung then transported through the blood.