title: Effect of Long-Term Antiorthostatic Suspension in a Murine Model of Acute Lung Injury.
abstract: OBJECTIVE
  Antiorthostatic suspension (AOS) is ground-based model of simulated microgravity. There is still no study about the effect of long-term microgravity on the clinical course of acute lung injury. We evaluated the effect of simulated microgravity using AOS in a murine model of acute lung injury by lipopolysaccharide (LPS).
  
  
  METHODS
  Thirty BALB/c mice were used. During 4 weeks, mice were equally allocated to control (free movement), restraint (tail suspended, but hindlimbs not unloaded), and AOS group (hindlimb unloaded). After then, mice got intranasal challenge with LPS (20 mg/kg, 50 μL). We measured: weight gain before and after AOS, the number of inflammatory cells and titers of cytokines (interleukin [IL]-1β, IL-6, IL-10, tumor necrosis factor-α, and interferon-γ) in bronchoalveolar lavage (BAL) fluid, titer of myeloperoxidase (MPO) in serum and lung homogenate, and histopathologic examination of lung tissue.
  
  
  RESULTS
  AOS group had significant weight loss compared to control and restraint group (P<0.001). AOS group also showed significantly decreased lymphocytes (P=0.023) compared to control group. In AOS group, titer for IL-1β in BAL fluid was significantly lower than restraint group (P=0.049). Titer for serum MPO was significantly decreased in AOS group compared to restraint group (P=0.004). However, there was no significant difference of MPO titers in lung tissue between groups. Histopathologic examination of lung tissue revealed no significant difference in the degree of pulmonary infiltration between restraint and AOS group.
  
  
  CONCLUSIONS
  In spite of modest anti-inflammatory effect, prolonged AOS caused no significant change in LPS-induced pulmonary inflammation.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Inha University School of Medicine, Incheon, Korea.
authors.forename: Tae Young
authors.initials: TY
authors.lastname: Jang
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Inha University School of Medicine, Incheon, Korea.
authors.forename: Ah-Yeoun
authors.initials: AY
authors.lastname: Jung
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Inha University School of Medicine, Incheon, Korea.
authors.forename: Young Hyo
authors.initials: YH
authors.lastname: Kim
keywords: Acute Lung Injury; Hindlimb Suspension; Lipopolysaccharides