Abstract

Thirty-six guinea pigs were exposed to an atmosphere containing gadolinium oxide dust for 6 hr per day, 5 days per week, for 40, 80 or 120 exposure days. An equal number of animals were exposed to an identical atmosphere without gadolinium oxide dust. After exposure, compliance measurements were made on the excised lungs and the results were plotted as elastance curves. Lung tissues were evaluated histologically. Analysis of variance of the slopes of the elastance curves showed a significant interaction between treatment and duration of exposure. A highly significant linear trend in the exposed groups indicated that the longer the exposure the less elastic were the lungs. Histologically, lesions became more severe as exposure time increased. These changes included alveolar cell hypertrophy, septal cell thickening, lymphoid hyperplasia and macrophage formation.