Hypothermia protects cultured human retinal pigment epithelial cells against indocyanine green toxicity.
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.
Kunikata
Hiroshi
H
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
Tomita
Hiroshi
H
Abe
Toshiaki
T
Murata
Hiromi
H
Sagara
Yoshiko
Y
Sato
Hajime
H
Wada
Yuko
Y
Fuse
Nobuo
N
Nakagawa
Yoichi
Y
Tamai
Makoto
M
Nishida
Kohji
K
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
D004396:Coloring Agents; D007208:Indocyanine Green