Peroxidase activities in the hamster bronchoalveolar lining fluid: modifications induced by exposure to silica dust.

The modifications of peroxidase (Po) activity have been studied in bronchoalveolar lavage fluid (BALF) from hamsters exposed to silica dust. In silica-treated animals, the mean total BALF-Po activity was significantly increased compared to control animals. This increased activity was accompanied by an influx of polymorphonuclear neutrophils in airways. HPLC gel filtration of BALF from control animals separated 5 peaks with Po activity. They had an apparent molecular weight of 140, 110, 80, 57, and 42 kDa. In BALF from silica-exposed animals, with the exception of the 57-kDa fraction, the same peaks were found. Additional fractions with an apparent molecular weight of greater than 200, 180, 92, 65, and 20 kDa were detected. All the fractions but those at 57 and 92 kDa were detectable in a whole-blood homogenate. Exposing hamsters to silica induced both quantitative modifications and a different pattern of BALF proteins having Po activity in the alveolar lining fluid.