EARLY PROTEIN OXIDATION IN THE NEONATAL LUNG IS RELATED TO DEVELOPMENT OF CHRONIC LUNG-DISEASE

Free radical-mediated oxidation of proteins may impair their function and cause cellular damage. We studied pulmonary protein oxidation and its association with the development of chronic lung disease in 61 new born infants (mean gestational age 31.1 +/- 4.0, range 24-41 weeks) re quiring intensive care with oxygen therapy. Protein oxidation was quan tified as protein carbonylation in tracheal aspirates recovered daily during the first week of life. Mean carbonyl concentration was 3.5 +/- 1.6 mu mol/mg protein. Negative correlations existed between protein carbonylation during days 2-4 and gestational age (day 2:r = -0.37, p = 0.01; day 3:r = -0.48, p = 0.001; and day 4:r = -0.33, p = 0.03). Pa tients who developed bronchopulmonary dysplasia showed significantly h igher protein carbonylation on days 1-6 (all p < 0.05). In multiple re gression analysis explaining bronchopulmonary dysplasia, using gestati onal age, inspired oxygen on days 1-3 and protein carbonylation on day 3 as independent variables, only protein carbonylation remained signi ficant. We conclude that immaturity is the most important factor expla ining free radical-mediated pulmonary protein oxidation in newborn inf ants and that oxidation of proteins is related to the development of c hronic lung disease.