Rabbit lungs after long-term exposure to low nickel dust concentration. II. Effects on morphology and function.

For 4 and 8 months (5 days/week, 6 hr/day) rabbits were exposed to 0.13 +/- 0.05 (mean +/- SD) mg/m3 of metallic nickel dust. Volume density of alveolar type II cells was estimated with electron microscopy. Lavaged alveolar macrophages were studied with light and electron microscopy and their abilities to reduce nitroblue tetrazolium (NBT) and to phagocytize particles were tested. The effects seemed to be similar after 4 and 8 months of exposure and when the exposed animals were combined, volume density of type II cells was increased and also significantly correlated with concentration of disaturated phosphatidylcholines in the lung. The macrophages had an active surface. Their NBT activity at rest was increased but a further increase during stimulation with E. coli was low, suggesting an impaired function. Phagocytic activity, however, was not significantly changed.