title: Role of mechanical stretching and lipopolysaccharide in early apoptosis and IL-8 of alveolar epithelial type II cells A549.
abstract: OBJECTIVE
  To investigate the effects of mechanical stretching and lipopolysaccharide (LPS) on the early apoptosis and IL-8 production of alveolar epithelial type II cells A549.
  
  
  METHODS
  The experimental matrix consisted of three integrated studies. In the first study, A549 cells were subjected to different stretching strain frequency and duration time to see the effects on the early apoptosis. In the second study, A549 cells were subjected to mechanical stretch (15% 4 h, 0.5 Hz) and LPS (1 or 100 ng/mL) to see whether mechanical strain and LPS also have an addictive effect on the early apoptosis. In the third study to investigate whether this addictive effect could be induced by LPS and mechanical stretch on IL-8 production, A549 cells were subjected to LPS (100 ng/mL) and mechanical strain (15%, 0.5 Hz, 4 h). Real time PCR and enzyme linked immunosorbent assay were used to measure mRNA and protein level of IL-8. The early apoptosis was detected by flow cytometry.
  
  
  RESULTS
  Mechanical stretch induced the early apoptosis in a force and frequency and time-dependent manner. In the presence of LPS, mechanical stretch enhanced LPS-induced early apoptosis, especially in 100 ng/mL LPS group compared with 1 ng/mL LPS and the control group. Mechanical stretch increased IL-8 production and enhanced LPS-induced IL-8 screation both in mRNA and protein levels.
  
  
  CONCLUSIONS
  Mechanical stretch can induce the early apoptosis and IL-8 secretion. Mechanical stretch and LPS have an addictive effect on the early apoptosis and IL-8 production in alveolar type 2 cells, which is one of the mechanisms of ventilator-induced lung injury.
authors: Department of Anesthesiology, Hainan Provincial Hospital, Haikou 570311, P.R. China.
authors: Qiao-Ming
authors: QM
authors: Ning
authors: Xiao-Ning
authors: XN
authors: Sun
authors: Xin-Kai
authors: XK
authors: Zhao
mesh_terms: D056809:Alveolar Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D015415:Biomarkers; D016209:Interleukin-8; D008070:Lipopolysaccharides; C482199:lipopolysaccharide, E coli O55-B5