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.
Kunikata
Hiroshi
H
Department of Ophthalmology and Visual Science, Tohoku University Graduate School of Medicine, Sendai, Japan. kunikata@oph.med.tohoku.ac.jp
Tomita
Hiroshi
H
Murata
Hiromi
H
Sagara
Yoshiko
Y
Sato
Hajime
H
Wada
Yuko
Y
Fuse
Nobuo
N
Nakagawa
Yoichi
Y
Abe
Toshiaki
T
Tamai
Makoto
M
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