Progressive lung injury over a one-year period after a single inhalation exposure to beryllium sulfate

The chronic pulmonary toxicity of beryllium sulfate was examined in rats over a 1-yr period after a single, 1-h exposure. Male rats, exposed in a nose-only inhalation chamber to an aerosol of 4.05 micrograms Be/L, were evaluated for lung toxicity by the methods of bronchoalveolar lavage, lung cell kinetics, and histopathologic analysis. Bronchoalveolar lavage activities for alkaline phosphatase (Alk Pase) and acid phosphatase (Ac Pase) were elevated 3 wk after exposure; lactate dehydrogenase (LDH) and Alk Pase activities peaked 3 months after exposure. Histopathologic analysis revealed progressive focal interstitial pneumonitis with a prominent alveolar component of heteromorphic macrophages, neutrophils, and debris. No increase was noted in the overall labeling index in the alveolar cell population at any of the time points sampled. This study demonstrates the effectiveness of bronchoalveolar lavage fluid analysis in monitoring lung damage over a prolonged period and shows that the pulmonary toxicity of beryllium manifests itself as a progressive lesion from a single 1-h inhalation exposure to BeSO4.