L-glutamate can protect the oxidative stress injuries of the fetal lung cells

Abstract

Abstract Background: Bronchopulmonary dysplasia (BPD) is one of the major complications of prematurity resulting in significant mortality and morbidity. Reactive oxygen species, which are highly reactive molecules that can cause oxidative damage to lung tissue and trigger inflammatory reactions, are associated with pathophysiological changes in many lung diseases, such as BPD. Hydrogen peroxide (H2O2), which is a strong oxidant, is widely used in simulating cellular oxidative damage. Whether glutamine can protect lung cells from oxidant damages is not known. Objectives: To explore the cytotoxic mechanisms of H2O2 on lung cells, including A549 and HEL299 cells, and investigate the effects of L-glutamine in the protection of oxidative damage on the lung cells. Methods: Cytotoxic effects of H2O2 and the protective effects of glutamine against H2O2 on lung cells were accessed by the cell viability assay. The underlying mechanisms for H2O2 damaging lung cells were analyzed by the flow cytometry to quantify changes in mitochondrial membrane potential before and after H2O2 and L-glutamine were added into lung cells. Pulmonary alveolar epithelial cells line, A549, and human embryonic bronchial fibroblast cell line, HEL 299, were grown in the incubator. H2O2 with and without L-glutamine was added in the lung cells, and cell viability was measured by the water-soluble tetrazolium 1 (WST-1) assay and the changes of mitochondrial membrane potential by the flow cytometry. Statistical analysis used is as follows: data comparisons from cell proliferation studies were analyzed by one-way analysis of variance. The quantification data of the mitochondrial potential assay was analyzed by Student’s t tests. A P-value of less than 0.05 was considered statistically significant. Results: A total of 100-μM H2O2 significantly decreased the viability of A549 and HEL299 cells; 8-mM L-glutamine rescued lung cell death caused by the H2O2 toxicity; and 100 μM of mitochondrial membrane potential was significantly elevated in HEL299 cells, except A549 cells in the application of H2O2 and L-glutamine. Conclusion: H2O2-induced cytotoxicity in A549 and HEL299 cells was associated with mitochondria. The different effects of L-glutamine on A549 and HEL299 cells in response to the 100 μM of H2O2-induced cytotoxicity suggest that these two cell lines may have different mechanisms against oxidative stress.