title: Hypothermia protects cultured human retinal pigment epithelial cells against indocyanine green toxicity.
abstract: OBJECTIVE
  The aim of this study was to determine whether indocyanine green (ICG) is toxic to cultured human retinal pigment epithelial (ARPE-19) cells, and whether hypothermia can protect the ARPE-19 cells against the ICG toxicity.
  
  
  METHODS
  Cultured ARPE-19 cells were exposed to 0.25, 0.5, 1, 2.5, and 5 mg/mL of ICG dye at 37 and 4 degrees C for 30 min. The percentage of ARPE-19 cells that survived was determined by resazurin 1 day after the exposure.
  
  
  RESULTS
  Exposure of the RPE cells to a hypotonic saline solution with an osmolarity equal to 5 mg/mL of ICG did not induce a statistically significant decrease in the percentage of RPE cells that survived. Exposure of the ARPE-19 cells to ICG induced a significant decrease in the percentage of cell survival at all concentrations of ICG (P<0.05), except in 0.25 mg/mL at 37 degrees C. At 4 degrees C, on the other hand, ICG induced a statistically significant decrease in the percentage of RPE cell survival only at 5 mg/mL of ICG (P<0.05).
  
  
  CONCLUSIONS
  These results indicate that ICG is toxic to human RPE cells in culture, and that cell death cannot be attributed to the low osmolarity. Hypothermia of 4 degrees C has a protective effect against ICG toxicity.
authors.affiliation: Department of Ophthalmology and Visual Science, Tohoku University Graduate School of Medicine, Sendai, and Ishinomaki Red Cross Hospital, Miyagi, Japan. kunikata@oph.med.tohoku.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kunikata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tomita
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Abe
authors.forename: Hiromi
authors.initials: H
authors.lastname: Murata
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Sagara
authors.forename: Hajime
authors.initials: H
authors.lastname: Sato
authors.forename: Yuko
authors.initials: Y
authors.lastname: Wada
authors.forename: Nobuo
authors.initials: N
authors.lastname: Fuse
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Tamai
authors.forename: Kohji
authors.initials: K
authors.lastname: Nishida
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects; D004396:Coloring Agents / Q000633:toxicity*; D019610:Cytoprotection; D064420:Drug-Related Side Effects and Adverse Reactions / Q000517:prevention & control*; D006801:Humans; D007036:Hypothermia, Induced; D007208:Indocyanine Green / Q000633:toxicity*; D010857:Pigment Epithelium of Eye / Q000166:cytology* / Q000187:drug effects
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green