Effect of bronchoalveolar lavage on the ultrastructure of the tracheal epithelium in rabbits.

Serious damage to the tracheal epithelium due to bronchoalveolar lavage (BAL) was recorded. Immediately after BAL 99 +/- 2% of goblet cells were exhausted and degenerated. Their regeneration began 24 h after BAL resulting in hyperplasia of goblet cells with the formation of endoepithelial mucous glands. The most pronounced injury to the ciliated cells was apparent 2 h after BAL. BAL markedly impaired the ciliary border. The mean number of cilia/microns 2 fell to 1.5 +/- 0.3/microns 2, then gradually rose to 7.5 +/- 0.5/microns 2 (controls 9.7 +/- 0.5/microns 2). The morphological signs of impairment of the self-cleaning ability of the epithelium were the most pronounced after 24 h and were still present at the end of the experiment.