Airway inflammation is important in diseases such as asthma and cystic fibrous. PMN remain in contact with airway epithelium until removed by macrophage phagocytosis and mucociliary clearance. Line is known about how PMN injure me airway epithelium. To investigate this question, we compared injury of human bronchial epithelial cells (BEAS 2B cell line) in vitro when incubated with H2OA, freshly isolated human PMN, or senescent PMN (aged overnight in F12 media or 5% serum). BEAS cell DNA was labeled by overnight incubation with BrdU. Cells were then co-incubated for 4 hours at 37°C with increasing concentrations of H2O2 or fresh or senescent PMN. BrdU release was determined by ELISA in the supernatants of BEAS cells (indicator of necrosis), and in BEAS cells treated with lysis buffer, lysates, (an indicator of DNA fragmentation). Treatment of BEAS cells with H2O2 (0.25-10mM) did not cause BrdU release in supernatants (O.D.=0.08 vs. 0.07 control) and only 10 mM H2O2 produced BrdU release from BEAS lysates (O.D.=0.27). Co-incubation of freshly isolated PMN with BEAS (4×104) produced dose-dependent BrdU release in both supernatant and lysate tractions, as did senescent PMN. Fresh PMN Sup (O.D.) Lys (O.D.) Aged PMN Sup(O.D.) Lys(O.D.) 4×103 0.13 0.15 0.32 0.30 4×104 0.25 0.22 0.47 0.46 4×105 0.39 0.40 0.25 0.21 Co-incubation of BEAS cells with PMN released more BrdU than incubation with H2O2 Senescent PMN were nearly as potent as fresh PMN at injuring BEAS cells. We conclude that senescent PMN in the airway may contribute to injury of respiratory epithelium.
|Original language||English (US)|
|Journal||Journal of Investigative Medicine|
|State||Published - 1996|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)