title: In vitro models for glaucoma research: effects of hydrostatic pressure.
abstract: OBJECTIVE
  The response of cells (e.g., optic nerve head [ONH] cells) to mechanical stress is important in glaucoma. Studies have reported the biological effects of hydrostatic pressure on ONH cells cultured on a rigid substrate. An apparatus, designed to independently vary hydrostatic pressure and gas tension (including oxygen tension) in culture medium, was used to evaluate the effects of pressure and tension on cell migration, shape, and α-tubulin architecture in a transformed cell line (DITNC1 rat cortical astrocytes).
  
  
  METHODS
  During the assay period, cells were exposed to one of four experimental configurations: (1) control pressure and control gas tension; (2) high-pressure (7.4 mm Hg) and reduced gas tension; (3) control pressure and reduced gas tension; and (4) high-pressure and control gas tension.
  
  
  RESULTS
  Calculations suggested that the cells in configurations 2 and 3 were hypoxic, as confirmed by direct measurements in configuration 2. No effects of hydrostatic pressure were observed on cell migration or α-tubulin architecture. However, cells cultured under low gas tension (configurations 2 and 3) showed increased migration at 48 and 72 hours (P < 0.05).
  
  
  CONCLUSIONS
  A hydrostatic pressure of 7.4 mm Hg has no effect on DITNC1 astrocytes cultured on rigid coverslips, whereas hypoxia associated with a fluid column creating this pressure does. These results differ from those in a previous report, the results of which may be explained by altered gas tensions in the culture medium. Steps are recommended for control of secondary effects when testing the effect of pressure on cultured cells.
authors.affiliation: Department of Bioengineering, Imperial College London, London, United Kingdom.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lei
authors.forename: Shadi
authors.initials: S
authors.lastname: Rajabi
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Pedrigi
authors.forename: Darryl R
authors.initials: DR
authors.lastname: Overby
authors.forename: A Thomas
authors.initials: AT
authors.lastname: Read
authors.forename: C Ross
authors.initials: CR
authors.lastname: Ethier
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology* / Q000502:physiology; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000502:physiology*; D048430:Cell Shape / Q000502:physiology*; D003470:Culture Media; D004027:Diencephalon / Q000166:cytology; D006874:Hydrostatic Pressure; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D051381:Rats; D014404:Tubulin / Q000378:metabolism*
chemical_list: D003470:Culture Media; D014404:Tubulin; D010100:Oxygen