Relationship between the levels of membrane lipid peroxidation and the glutathione peroxidase of normal and diseased lung cells

Aim. The alveolar epithelium of human lower respiratory tract is susceptive to the deleterious effects of reactive oxigen metabolites (ROM) derived from different sources, including inhaled pollutants and inflammatory cells. The high levels of ROM produce the peroxidation of cell membrane phospholipids with consequent alteration of the normal function of pulmonary cells. These cells defend themselves against ROM by using anti-oxidant systems, including the glutathione peroxidase/glutathione reductase (GPX/GR) enzymatic system. In this study we evaluated the amount of lipoperoxides and of the enzymatic activity of glutathione peroxidase (GPX) in the bronchoalveolar lavage (BAL) cells of normal subjects and of patients with lung disease treated or not with prednisone. Methods. The study population consisted of 5 healthy individuals with acute or chronic lung disease without pharmacological treatment and 8 patients with pharmacological treatment. All individuals participating in this study underwent a broncoscopy with BAL. After preparation of BAL cells lipoperoxides concentration and GPX activity was evaluated. Results. Our results show that the untreated patients possess high levels of lipoperoxides in their BAL cells, while the GPX activity is lower than the one found in normal subjects. In contrast, in the BAL cells of treated patients the level of lipoperoxides is lower than the one detected in untreated patients, while there is an increase in the GPX activity in comparison with both normal subjects and untreated patients. Conclusion. In conclusion, these data show that prednisone could determine an increase in anti-oxidative defences in pulmonary cells.