Rabbit lungs after long-term exposure to low nickel dust concentration. I. Effects on phospholipid concentration and surfactant activity.

Rabbits were exposed for 4 or 8 months (5 days/week, 6 hr/day) to 0.13 +/- 0.05 mg/m3 (mean +/- SD) of metallic nickel dust. After exposure the left lung was homogenized and its content of phospholipids as well as the concentration and composition of the phosphatidylcholines were estimated. The right lung was lavaged and the surface tension of the lavage fluid was studied with a pulsating bubble technique. Both exposed groups showed a similar increase in total phospholipids, about 20% in the upper lobe and 30% in the lower lobe. The increase was mainly, possibly totally, due to an elevated level of phosphatidylcholines, especially disaturated species. Surface tension was significantly lower in exposed rabbits after 4 months of exposure but it was similar to that of the controls after 8 months.