The Pulmonary Epithelial Cell Line L2 as a New Model for an Inducible Nitric Oxide Synthase Expressing Distal Airway Epithelial Cell

Nitric oxide released in large amounts by inducible nitric oxide synthase (iNOS)-containing pulmonary cells plays an important role in many aspects of lung function in health and disease. The aim of this study was to establish a permanent non tumor-derived alveolar epithelial cell line that exhibits the typical characteristics of an iNOS-expressing cell. Therefore, the pulmonary epithelial cell line L2 (adult rat) was incubated with lipopolysaccharide derived from Escherichia coli (serotype 0111:B4) and different cytokines. The strongest effect on iNOS gene expression and nitric oxide release could be detected when L2 cells were coincubated with interferon-γ + tumor necrosis factor-α. iNOS complementary DNA concentration was 25 amol/μl at 9h, and nitrite/nitrate levels were 99.43 ± 3.97 nmol/106 cells at 24h, respectively. Our results show that L2 cells can be regarded as an appropriate model for investigating iNOS gene expression and nitric oxide functions in alveolar epithelial cells.