A STUDY OF THE LENGTH AND DIAMETER OF FIBRES, IN LUNG AND IN BRONCHO-ALVEOLAR LAVAGE FLUID, FOLLOWING EXPOSURE OF RATS TO CHRYSOTILE ASBESTOS

Abstract

This paper describes changes in the dimensions of fibres in the lungs of rats and in fibres removed from the lungs by broncho-alveolar lavage, following a single inhalation exposure to about 5mg m −3 of chrysotile asbestos for 5 h. The lengths and diameters of fibres were measured with the transmission electron microscope. In the 90-day period following exposure, there was a progressive increase in the mean length and decrease in the mean diameter of fibres in the lungs. For fibres recovered by broncho-alveolar lavage, both the mean length and diameter decreased with time. These findings indicate that short fibres are cleared preferentially from the lung and that chrysotile fibres progressively separate into individual fibrils.