Anoxia-reoxygenation versus ischemia in isolated rat lungs

Abstract

Oxidant generation in anoxia-reoxygenation and ischemia-reperfusion was compared in isolated rat lungs. Anoxia-reoxygenation was produced by N2 ventilation followed by O2 ventilation. After anoxia, lung ATP content was decreased by 59%. Oxygenated ischemia was produced by discontinuing perfusion while ventilation with O2 was maintained. With anoxia-reoxygenation, oxidant generation, evaluated by oxidation of dichlorodihydrofluorescein (H2DCF) to fluorescent dichlorofluorescein, increased 3.6-fold, lung thiobarbituric acid reactive substances (TBARS) increased 342%, conjugated dienes increased 285%, and protein carbonyl content increased 46%. Pretreatment of lungs with 100 μM allopurinol inhibited the reoxygenation-mediated increase in lung fluorescence by 75% and TBARS by 69%. Oxygenated ischemia resulted in an approximately eightfold increase in lung H2DCF oxidation and a fourfold increase in TBARS, but allopurinol had no effect. On the other hand, 100 μM diphenyliodonium (DPI) inhibited the ischemia-mediated increase in lung fluorescence by 69% and lung TBARS by 70%, but it had no effect on the increase with anoxia-reoxygenation. Therefore, both ischemia-reperfusion and anoxia-reoxygenation result in oxidant generation by the lung, but a comparison of results with a xanthine oxidase inhibitor (allopurinol) and a flavoprotein inhibitor (DPI) indicate that the pathways for oxidant generation are distinctly different.

Adenovirus-mediated transfer of the 1-cys peroxiredoxin gene to mouse lung protects against hyperoxic injury

“…TBARS are a well-accepted marker of oxidative modification of lipids, and the presence of carbonyl groups is taken as presumptive evidence of oxidative modification of proteins (3,5,15,25). In the present study, the increased lung content of TBARS and protein carbonyls in mice exposed to hyperoxia provides evidence of oxidative stress.…”

“…For tissue analysis, lung (1:10) in PBS containing 0.01% butylated hydroxytoluene was homogenized under N2. TBARS, protein carbonyls, and total protein in tissue homogenates were determined by spectrophotometric assay as previously described (3,25).…”

NOX Enzymes and Pulmonary Disease

“…Furthermore, recent studies indicate that activation of an EC-associated NOX may be the primary mechanism for ROS generation during reoxygenation after lung ischemia (5,152). Neutrophil NOX-derived ROS also contribute to organ injury after hemorrhagic shock in mice (29).…”

Efeito da ventilação com diferentes frações inspiradas de oxigênio e do alopurinol na isquemia-reperfusão pulmonar em ratos

“…Isso sugere que essa diferença é conseqüente da grande liberação de EROs, sendo parcialmente equilibrada pelo uso do antioxidante. O mesmo foi demonstrado por Zhao et al 49 , que também observaram a ação protetora do alopurinol em pulmões de ratos.…”

“…É um dos métodos mais comumente utilizados no estudo da lesão de isquemia-reperfusão tecidual 17,22,29,32,49 . O presente estudo mostrou uma tendência de aumento nos valores das TBARS nos pulmões submetidos à isquemia-reperfusão sem alopurinol.…”