title: Release of hydrogen peroxide by rat type II pneumocytes in the prolonged culture.
abstract: Type II pneumocytes (T II pneumocytes) produce hydrogen peroxide (H(2)O(2)), which may be potentially dangerous for the lung. These cells in culture differentiate to type I-like pneumocytes and it may reflect the differentiation which follows the injury of alveolar epithelium. This work was undertaken to estimate the H(2)O(2) release by T II pneumocytes, freshly isolated and cultured up to 8 days. The light and electron microscopy evaluation confirmed the differentiation of T II pneumocytes to type I-like cells. The release of H(2)O(2), estimated spectrofluorimetrically as homovanillic acid oxidation product obtained in the presence of horseradish peroxidase, was significantly higher at day 4 (0.63+/-0. 68nmol/mg protein/min, P</=0.02) and 6 (0.46+/-0.31, P</=0.001) compared to fresh cells (0.15+/-0.08). Phorbol esters increased H(2)O(2) release at day 2 (0.39+/-0.22 vs 0.16+/-0.08, P</=0.02) and the inhibition of protein kinase C resulted in the decrease at day 2 (0.14+/-0.06 vs 0.07+/-0.02, P</=0.025), day 6, (0.49+/-0.25 vs 0. 15+/-0.08, P</=0.005) and 8 (0.76+/-0.63 vs 0.23+/-0.29, P</=0.02). Inhibition of intracellular catalase resulted in a significant increase only at day 2 (0.23+/-0.1 vs 0.15+/-0.09, P</=0.05). Inhibition of mitochondrial respiratory chain decreased H(2)O(2) release at day 2 (0.13+/-0.11 vs 0.07+/-0.07, P</=0.002) and 4 (0. 75+/-0.88 vs 0.61+/-0.85, P</=0.002). These results indicate that alveolar epithelium may be a source of potentially dangerous ROS and that the cell differentiation is accompanied by the increase of H(2)O(2) production. Both mitochondrial respiratory chain and membrane-bound NADPH-oxidase may be responsible for the production of H(2)O(2) by T II pneumocytes.
authors.affiliation: Department of Pneumology and Allergology, Medical University of Lodz, Kopcinkiego 22, 90-153, Lodz, Poland.
authors.forename: W J
authors.initials: WJ
authors.lastname: Piotrowski
authors.forename: J
authors.initials: J
authors.lastname: Marczak
authors.forename: D
authors.initials: D
authors.lastname: Dinsdale
authors.forename: Z
authors.initials: Z
authors.lastname: Kurmanowska
authors.forename: Y
authors.initials: Y
authors.lastname: Tarasow
authors.forename: J
authors.initials: J
authors.lastname: Komos
authors.forename: D
authors.initials: D
authors.lastname: Nowak
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism; D002452:Cell Count; D002469:Cell Separation; D002478:Cells, Cultured; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008168:Lung / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D011190:Potassium Cyanide / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D006861:Hydrogen Peroxide; D002374:Catalase; D011493:Protein Kinase C; D011190:Potassium Cyanide; D013755:Tetradecanoylphorbol Acetate