title: Effects of hydroquinone on retinal and vascular cells in vitro.
abstract: OBJECTIVE
  To explore the molecular pathophysiology that might explain the epidemiologic association between cigarette smoke and age-related macular degeneration (AMD) by examining the effects of hydroquinone (HQ), a toxic compound present in high concentration in cigarette smoke-related tar, on human retinal pigment epithelial cells (ARPE-19), rat retinal neurosensory cells (R-28), and human microvascular endothelial cells (HMVEC).
  
  
  METHODS
  ARPE-19, R-28, and HMVEC were treated for 24 h with four different concentrations of HQ (500 μM, 200 μM, 100 μM, 50 μM). Cell viability, caspase-3/7 activation, DNA laddering patterns, and lactate dehydrogenase (LDH) levels were analyzed.
  
  
  RESULTS
  At 50 μM HQ, R-28 cells showed a significant decrease in cell viability compared with the dimethyl sulfoxide (DMSO)-treated controls. At the 100-500 μM concentrations, all three cell lines showed significant cell death (P < 0.001). In the ARPE-19, R-28, and HMVEC cultures, the caspase-3/7 activities were not increased at any of the HQ concentration.
  
  
  CONCLUSIONS
  Our findings suggest that the mechanism of cell death in all three cell lines was through non-apoptotic pathway. In addition, neuroretinal R-28 cells were more sensitive to HQ than the ARPE-19 and HMVEC cultures.
authors.affiliation: Department of Ophthalmology, Gavin S. Herbert Eye Institute, University of California, Irvine, CA, USA.
authors.forename: Ashish
authors.initials: A
authors.lastname: Sharma
authors.forename: Jayaprakash A
authors.initials: JA
authors.lastname: Patil
authors.forename: Ana L
authors.initials: AL
authors.lastname: Gramajo
authors.forename: Gail M
authors.initials: GM
authors.lastname: Seigel
authors.forename: Baruch D
authors.initials: BD
authors.lastname: Kuppermann
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Kenney
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D006873:Hydroquinones / Q000633:toxicity*; D008268:Macular Degeneration / Q000139:chemically induced / Q000235:genetics / Q000473:pathology*; D009153:Mutagens / Q000633:toxicity; D051381:Rats; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology
chemical_list: D006873:Hydroquinones; D009153:Mutagens; D053148:Caspase 3; D053179:Caspase 7; C031927:hydroquinone