cyclin-d1 and Acute-Lung-Injury

Oxidative stress is regarded as a key regulator in the pathogenesis of prolonged hyperoxia-induced lung injury, which causes injury to alveolar epithelial cells and eventually leads to development of bronchopulmonary dysplasia (BPD). Many studies have shown that hydrogen has a protective effect in a variety of cells. However, the mechanisms by which hydrogen rescues cells from damage due to oxidative stress in BPD remains to be fully elucidated. This study sought to evaluate the effects of hydrogen on hyperoxia-induced lung injury and to investigate the underlying mechanism. Primary type II alveolar epithelial cells (AECIIs) were divided into four groups: control (21% oxygen), hyperoxia (95% oxygen), hyperoxia + hydrogen, and hyperoxia + hydrogen + LY294002 (a PI3K/Akt inhibitor). Proliferation and apoptosis of AECIIs were assessed using MTS assay and flow cytometry (FCM), respectively. Gene and protein expression were detected by quantitative polymerase chain reaction (q-PCR) and western blot analysis. Stimulation with hyperoxia decreased the expression of P-Akt, P- FoxO3a, cyclinD1 and Bcl-2. Hyperoxic conditions increased levels of Bim, Bax, and Foxo3a, which induced proliferation restriction and apoptosis of AECIIs. These effects of hyperoxia were reversed with hydrogen pretreatment. Furthermore, the protective effects of hydrogen were abrogated by PI3K/Akt inhibitor LY294002. The results indicate that hydrogen protects AECIIs from hyperoxia-induced apoptosis by inhibiting apoptosis factors and promoting the expression of anti-apoptosis factors. These effects were associated with activation of the PI3K/Akt/FoxO3a pathway.

Topics: Acute Lung Injury; Alveolar Epithelial Cells; Animals; Apoptosis; bcl-2-Associated X Protein; Bcl-2-Like Protein 11; Cells, Cultured; Cyclin D1; Female; Forkhead Box Protein O3; Gene Expression; Genes, bcl-2; Hydrogen; Hyperoxia; Oxidative Stress; Phosphatidylinositol 3-Kinases; Pregnancy; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction

1. Pravastatin is best known for its antilipidemic action. Recent studies have shown that statins have immunomodulatory and anti-inflammatory effects. The present study aimed to determine whether or not pravastatin can attenuate acute lung injury and fibrosis in a mouse model. 2. Bleomycin was given to C57BL6 mice through intratracheal instillation. Pravastatin was given through intraperitoneal injection. To study the effect of pravastatin on the early inflammatory phase and the late fibrotic phase, mice were killed on days 3, 7, 14 and 21. 3. Pravastatin attenuated the histopathological change of bleomycin-induced lung injury and fibrosis. The accumulation of neutrophils and increased production of tumor necrosis factor-α in bronchoalveolar lavage fluid were inhibited in the early inflammatory phase. Pravastatin effectively inhibited the increase of lung hydroxyproline content induced by bleomycin. Furthermore, pravastatin reduced the increased expression of transforming growth factor (TGF)-β1, connective tissue growth factor (CTGF), RhoA and cyclin D1. The increased levels of TGF-β1 and CTGF mRNA expression were also significantly inhibited by pravastatin. 4. Pravastatin effectively attenuated bleomycin-induced lung injury and pulmonary fibrosis in mice. Our results provide evidence for the therapeutic potential of pravastatin in the treatment of acute lung injury and pulmonary fibrosis.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents; Bleomycin; Blotting, Western; Bronchoalveolar Lavage Fluid; Connective Tissue Growth Factor; Cyclin D1; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Gene Expression; Hydroxyproline; Mice; Mice, Inbred C57BL; Pravastatin; Pulmonary Fibrosis; Respiratory Distress Syndrome; Reverse Transcriptase Polymerase Chain Reaction; rho GTP-Binding Proteins; rhoA GTP-Binding Protein; Transforming Growth Factor beta1