Dynamic changes of constituents in bronchoalveolar lavage fluid in experimental silicotic rats.

Bronchoalveolar lavage (BAL) is a useful and safe method for sampling cellular and biochemical components from the lung. Analysis of bronchoaveolar lavage fluid (BALF) constituents is useful for defining the stage of disease, and for assessing disease progression and the response to therapy in lung disorders. We studied the dynamic changes in various indices for BALF and the accompanying silicotic changes in the lungs of rats at different times after quartz instillation. Total cell counts, LDH activity, protein concentration, and lipoperoxide (LPO) in the BALF of experimental silicotic rats were significantly higher than those of control rats (P < 0.05 or 0.01). After instillation, quartz content, total cell counts, LDH activity and protein concentration in BALF tended to decrease over time. These findings suggested that in acute silicosis, quartz can induce serious inflammation and damage the lung, with acute lung proteinosis seen as the main change in this stage.