Hypothermia of 8°C protects cultured retinal pigment epithelial cells and retinal ganglion cells against trypan blue toxicity

PURPOSE: To determine whether hypothermia of 8 degrees C can protect cultured human retinal pigment epithelial (ARPE-19) cells and rat retinal ganglion cells (RGC-5) against trypan blue (TB) toxicity. DESIGN: Laboratory investigation. METHODS: ARPE-19 cells and RGC-5 were exposed to balanced salt solution as controls, and 0.05% and 0.5% TB at 37 degrees C, and at 8 degrees C for one minute. The percentage of surviving cells was determined by the resazurin test. RESULTS: TB induced a statistically significant decrease in the percentage of ARPE-19 cells surviving at 0.5% TB at 37 degrees C (P <.01). Conversely, TB induced a statistically significant decrease in the percentage of RGC-5 surviving at all conditions except for 0.05% TB at 8 degrees C (0.05% 37 degrees C; P <.05, 0.5% 37 degrees C and 8 degrees C; P <.01). CONCLUSIONS: These results indicate that reducing the temperature to 8 degrees C has a protective effect against the TB toxicity for ARPE-19 cells and RGC-5 in culture.