Hypothermia protects cultured human retinal pigment epithelial cells against trypan blue toxicity.
OBJECTIVE
To determine whether trypan blue (TB) is toxic to cultured human retinal pigment epithelial (ARPE-19) cells, and whether hypothermia can protect ARPE-19 cells against TB toxicity.


METHODS
ARPE-19 cells were cultured and exposed to balanced salt solution as a control, while other cells were exposed to 0.05, 0.2, and 0.5% TB dye at 37 and 4 degrees C for 5 and 30 min. The percentage of ARPE-19 cells that survived was determined by resazurin 1 day after the exposure.


RESULTS
A statistically significant decrease in the percentage of ARPE-19 cells surviving was found after exposure to 0.2 and 0.5% TB at any temperature or for any exposure duration (p < 0.01). The percentage of RPE cells surviving at 0.05% was not significantly different from that of controls except for a 30-min exposure at 37 degrees C. The percentage of cells surviving at 4 degrees C for a 5-min exposure to 0.5% TB and a 30-min exposure to 0.2 and 0.5% was significantly higher than that at 37 degrees C under each condition (p < 0.01 for all).


CONCLUSIONS
These results indicate that TB is toxic to human RPE cells, and the toxicity is dose- and exposure duration-dependent. Exposing the cells at 4 degrees C had a protective effect against higher concentrations or longer exposure durations of TB compared to exposure at 37 degrees C.
Department of Ophthalmology and Visual Science, Tohoku University Graduate School of Medicine, Sendai, Japan. kunikata@oph.med.tohoku.ac.jp
Hiroshi
H
Kunikata
Hiroshi
H
Tomita
Hiromi
H
Murata
Yoshiko
Y
Sagara
Hajime
H
Sato
Yuko
Y
Wada
Nobuo
N
Fuse
Yoichi
Y
Nakagawa
Toshiaki
T
Abe
Makoto
M
Tamai
D002452:Cell Count; D002470:Cell Survival; 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; D066298:In Vitro Techniques; D010857:Pigment Epithelium of Eye / Q000166:cytology* / Q000187:drug effects; D014343:Trypan Blue / Q000633:toxicity*
D004396:Coloring Agents; D014343:Trypan Blue