2-4-dinitrophenylhydrazine and Lung-Diseases

Hyperoxia, used therapeutically in the treatment of respiratory insufficiencies, can cause lung injury, probably through the actions of reactive oxygen species. The present studies were designed to test the hypothesis that oxidation of specific proteins would provide useful biomarkers of the onset of tissue injury, and thereby provide clues as to the mechanisms responsible. We exposed adult male Sprague-Dawley rats to room air or to greater than 95% O2 for 60 h and examined proteins in pleural effusion and broncho-alveolar lavage (BAL) fluids, and in lung tissue homogenates and subfractions. Oxidation of protein thiols was assessed by derivatization with monobromobimane, separation by electrophoresis, and visualization of the fluorescent thioether derivatives. Derivatization with 2,4-dinitrophenylhydrazine (DNPH), electrophoresis, and western analysis was employed to assess a different class of oxidative modifications, frequently termed 'protein carbonyls'. In addition, we investigated the effects of the 21-aminosteroid U-74389G, 10 mg/kg, given intraperitoneally every 12 h, on biomarkers of protein oxidation and on manifestations of lung injury. Hyperoxia caused lung injury evidenced by pleural effusions, increases in BAL protein concentrations, and pulmonary edema; U-74389G attenuated the first two indices of lung injury, but did not alter edema. Protein thiol status of the fractions studied were not affected notably by hyperoxia, or by the aminosteroid. The formation of DNPH-reactive sites on a limited number of proteins by hyperoxia was observed, and some of these effects were attenuated in the animals given U-74389G. Histological examination of lung tissues showed accumulation of intra-alveolar protein exudates in hyperoxic rats, and a significant attenuation of this effect was observed in the animals treated with U-74389G. In conclusion, studies of shifts in protein thiol status that may be caused by hyperoxia will require increasingly specific methods of analysis, and characterization of the specific DNPH-reactive proteins formed in hyperoxia may provide critical insights into the mechanisms of lung injury. Administration of U-74389G offers some degree of protection against hyperoxia and attenuation of these biomarkers of oxidation, but the precise mechanisms by which this protection is effected will require additional study.

Topics: Animals; Antioxidants; Biomarkers; Bronchoalveolar Lavage Fluid; Hyperoxia; Lung Diseases; Male; Phenylhydrazines; Pregnatrienes; Proteins; Rats; Rats, Sprague-Dawley; Sulfhydryl Compounds

To develop a method capable of quantifying the oxidative modification of proteins in pulmonary fluid obtained during routine suctioning of neonates receiving ventilation, thus providing an integrated assessment of antioxidant defenses.. Consecutive sample of neonates receiving ventilation.. Neonatal intensive care unit.. Twenty-six neonates receiving ventilation with a gestational age of 24 to 42 weeks, from whom 246 samples were collected and analyzed.. The carbonyl content in the lavage samples was measured by reaction with 2,4-dinitrophenylhydrazine followed by high-pressure liquid chromatography. Oxidation of proteins caused introduction of carbonyl groups into the side chains of the protein, providing a convenient and relatively specific marker of oxidative damage. On the first day of life, the initial protein-bound carbonyl for each neonate was usually low and consequently was not significantly related to birth weight, gestational age, or initial ventilatory requirements. Examination of the changes in pulmonary protein carbonyl in the first days of life revealed correlations of interest. In the first day of life, four neonates whose average inspired oxygen were < 40% showed no increase in carbonyl content, whereas four neonates whose inspired oxygen was > 40% showed an average increase in carbonyl of 51% (P < .001). Also, the need for ventilation > 3 days was correlated with elevated carbonyl in those first 3 days. The carbonyl content averaged over the first 3 days was 0.13 +/- 0.02 mol carbonyl/mol protein for the eight neonates receiving ventilation < 72 hours, whereas the nine needing longer ventilation had a carbonyl content of 0.28 +/- 0.03 mol carbonyl/mol protein (P < .05). Seven neonates were treated with dexamethasone because of ventilator dependence at 14 days of age. In these neonates, treatment was associated with a 50% reduction in carbonyl content within 48 hours (P < .02).. Oxidative damage to pulmonary proteins can be quantitated in samples obtained during routine suctioning of neonates receiving ventilation. The amount of oxidatively modified protein may provide a quantitative assessment of oxygen toxicity and of pulmonary antioxidant defenses.

Topics: Bronchoalveolar Lavage Fluid; Chromatography, High Pressure Liquid; Chronic Disease; Dexamethasone; Female; Humans; Infant, Newborn; Infant, Newborn, Diseases; Ketones; Lung; Lung Diseases; Male; Oxidation-Reduction; Oxygen; Phenylhydrazines; Proteins; Respiration, Artificial; Respiratory Distress Syndrome, Newborn