Responses of Rat Lungs Following Inhalation of Beryllium Metal Particles to Achieve Relatively Low Lung Burdens.

Potential health effects resulting from the accidental exposure of people to beryllium metal are of concern. To investigate the effects of relatively low levels of beryllium metal on lung clearance, we simuitaneously exposed rats to beryllium metal and radioactive tracer particles. Exposure to beryllium metal aerosol to achieve estimated lung burdens of 9 or 52 μg significantly retarded clearance up to 365 days after exposure compared to controls, whereas lung burdens of 1.5 or 2 μg had no significant effect on clearance. Groups of rats were sacrificed at 8,16,40,90,210 and 365 days after exposure for bronchoalveolar lavage. The total numbers of cells, incidence of neutrophils, the levels of total protein, and the enzymes lactate dehydrogenase and β-glucuronidase were generally elevated in lavage fluids from groups of rats that also had impaired lung clearance. This study serves to further define the levels of beryllium metal required to retard lung clearance and induce accompanying pathological responses in the lungs of rats. [ABSTRACT FROM PUBLISHER]