title: Effect of cysteamine on oxidative stress-induced cell death of human corneal endothelial cells.
abstract: OBJECTIVE
  The principal objective of this study was to evaluate the protective effect of cysteamine against the oxidative stress-induced cell death of human corneal endothelial cells.
  
  
  METHODS
  In this study, human corneal endothelial cells (HCECs) were cultured according to a previously published method. With treatment of 0 mM or 5 mM of tert-butyl hydroperoxide (tBHP) with various concentrations (0-50 mM) of cysteamine, reactive oxygen species (ROS) production was measured using an oxidation-sensitive fluorescent probe, and dichlorofluorescein diacetate (DCFH-DA) methods. Cell viability was assayed via the Cell Counting Kit-8 method. The levels of cellular glutathione were also assessed enzymatically with glutathione reductase using a commercial glutathione assay kit (Cayman Chemical, USA).
  
  
  RESULTS
  This study showed that cysteamine reduced 2',7'-dihydrodichlorofluorescein oxidation and increased glutathione. Cysteamine significantly inhibited tBHP-induced ROS production. Cysteamine-treated cells evidenced higher viability relative to the controls at 5 mM tBHP, and cysteamine also effectively protected HCECs against ROS-induced cell death via an increase in intracellular glutathione.
  
  
  CONCLUSIONS
  Our data indicate that cysteamine was not toxic at low concentrations and, at high concentrations, protects HCECs against oxidative injury-mediated cell death via the inhibition of ROS production, although cysteamine is toxic in cells at high concentrations without oxidative stress.
authors.affiliation: Department of Ophthalmology, Hallym University College of Medicine, Seoul, Republic of Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Shin
authors.forename: Jong Mo
authors.initials: JM
authors.lastname: Seo
authors.forename: Tae Young
authors.initials: TY
authors.lastname: Chung
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Hyon
authors.forename: Won Ryang
authors.initials: WR
authors.lastname: Wee
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000187:drug effects*; D002470:Cell Survival; D002478:Cells, Cultured; D003543:Cysteamine / Q000494:pharmacology*; D004728:Endothelium, Corneal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005452:Fluoresceins / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D020122:tert-Butylhydroperoxide / Q000633:toxicity
chemical_list: C109098:2,7-dihydrodichlorofluorescein diacetate; D005452:Fluoresceins; D017382:Reactive Oxygen Species; D003543:Cysteamine; D020122:tert-Butylhydroperoxide; D005978:Glutathione