Oxygen toxicity in mouse lung: pathways to cell death.
Mice exposed to 100% O2 die after 3 or 4 d with diffuse alveolar damage and alveolar edema. Extensive cell death is evident by electron microscopy in the alveolar septa, affecting both endothelial and epithelial cells. The damaged cells show features of both apoptosis (condensation and margination of chromatin) and necrosis (disruption of the plasma membrane). The electrophoretic pattern of lung DNA indicates both internucleosomal fragmentation, characteristic of apoptosis, and overall degradation, characteristic of necrosis. Hyperoxia induces a marked increase in RNA or protein levels of p53, bax, bcl-x, and Fas, which are known to be expressed in certain types of apoptosis. However, we did not detect an increased activity of proteases belonging to the apoptosis "executioner" machinery, such as CPP32 (caspase 3), ICE (caspase 1), or cathepsin D. Furthermore, administration of an ICE-like protease inhibitor did not significantly enhance the resistance to oxygen. Additionally, neither p53-deficient mice nor lpr mice (Fas null) manifested an increased resistance to hyperoxia-induced lung damage. These results show that both necrosis and apoptosis contribute to cell death during hyperoxia. Multiple apoptotic pathways seem to be involved in this, and an antiapoptotic strategy does not attenuate alveolar damage.
Departments of Pediatrics and Pathology, University of Geneva, Switzerland. Constance.Barazzone@medecine.unige.ch
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Barazzone
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Horowitz
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Donati
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Rodriguez
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Piguet
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000276:immunology; D015153:Blotting, Western; D020170:Caspase 1 / Q000378:metabolism; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002402:Cathepsin D / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D053222:Fas Ligand Protein; D015870:Gene Expression / Q000276:immunology; D018496:Hyperoxia / Q000378:metabolism / Q000503:physiopathology; D020287:In Situ Nick-End Labeling; D008171:Lung Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology*; D008562:Membrane Glycoproteins / Q000032:analysis / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009336:Necrosis; D010100:Oxygen / Q000633:toxicity*; D011518:Proto-Oncogene Proteins / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D011650:Pulmonary Alveoli / Q000737:chemistry / Q000201:enzymology / Q000473:pathology*; D012333:RNA, Messenger / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000235:genetics; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D019014:fas Receptor / Q000032:analysis / Q000235:genetics
D000590:Amino Acid Chloromethyl Ketones; C494827:Bax protein, mouse; C494812:Bcl2l1 protein, mouse; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D019014:fas Receptor; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D020170:Caspase 1; D002402:Cathepsin D; D010100:Oxygen