title: Effects of simulated weightlessness on the release of PGE2 in rat calvarial osteoblasts induced by flow shear stress.
abstract: OBJECTIVE
  To observe the effects of simulated weightlessness on the release of prostaglandin E2 in rat calvarial osteoblasts by flow shear stress (FSS).
  
  
  METHODS
  Osteoblasts were isolated from neonatal rat calvariae and then were set to two groups. One was cultured in 1 G terrestrial gravitational environment. The other was cultured on a clinostat (simulating weightlessness environment) for 60 h, then the osteoblasts were treated with 0.5 Pa or 1.5 Pa FSS in a flow chamber for 1 h. Then release of PGE2 in the osteoblasts was determined.
  
  
  RESULTS
  0.5 Pa and 1.5 Pa FSS treatments significantly increased the release of PGE2 in osteoblasts cultured in 1 G environment (P < 0.01) , but there was no remarkable difference between the responses of 0.5 Pa FSS treatment group and 1.5 Pa group (P > 0.05). By contrast, in cells cultured in simulated weightlessness environment, no detectable release of PGE2 was found with the treatment of 0.5 Pa FSS (P < 0.01). The release of PGE2 was delayed and the amount of PGE2 Production was remarkably decreased with 1.5 Pa FSS treatment (P < 0.01).
  
  
  CONCLUSIONS
  These results demonstrated that the responsiveness of osteoblasts to FSS was down-regulated in simulated weightlessness.
authors.affiliation: Department of Aerospace Medicine, The Fourth Military Medical University, Xi' an 710032.
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.forename: X Y
authors.initials: XY
authors.lastname: Wu
authors.forename: Y H
authors.initials: YH
authors.lastname: Li
authors.forename: X Y
authors.initials: XY
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D002478:Cells, Cultured; D015232:Dinoprostone / Q000378:metabolism*; D010006:Osteoblasts / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012212:Rheology; D012399:Rotation; D015398:Signal Transduction / Q000502:physiology*; D012886:Skull / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D013314:Stress, Mechanical; D018474:Weightlessness Simulation
chemical_list: D015232:Dinoprostone