Free lung cell phagocytosis and lysosomal enzyme activity after inhalation of lipopolysaccharide in guinea-pigs.

Free lung cells were studied in guinea-pigs different times after an inhalation exposure to bacterial endotoxin yielding a dose of about 1 microgram/animal. After exposure the number of alveolar macrophages (AM) and neutrophils was increased. The phagocytosis capacity of the lung was increased, mainly due to the influx of neutrophils. The activity of N-acetyl-beta-D-glucosaminidase from exposed animals was decreased in AM cell cultures and increased in lavage fluid 2 hours and later after exposure. Cathepsin D activity was also decreased in AM cell cultures but did not change in lavage fluid. Lactate dehydrogenase was increased in lung lavage fluid. The results show that LPS inhalation activates AM and that increased amounts of lysosomal enzymes are present in the airways.