Effect of Brilliant Blue G on the Retinal Ganglion Cells of Rats

In Brief Purpose: To investigate the effects of Brilliant Blue G (BBG) on rat retinal ganglion cells (RGCs), both in vitro and in vivo. Methods: In vitro, rat RGCs were purified by a 2-step immunopanning procedure, briefly exposed to BBG (250 mg/L), and irradiated with an endoilluminator for 15 minutes or incubated in the presence of BBG (concentration, 2–250 mg/L) without irradiation. The number of viable RGCs was counted after 3 days in culture. In vivo, after rats received an intravitreal injection of 3 μL of BBG (0.25 and 2.5 mg/L), the number of viable RGCs was examined by a 1,1'-dioctadecyl-1-3,3,3',3'-tetramethylindocarbocyanine perchlorate–retrolabeling technique. Results: In vitro, a brief exposure to BBG and irradiation did not affect RGC survival. However, BBG reduced the number of viable RGCs in a dose-dependent manner when the cells were exposed for 3 days. In vivo, when rats received an intravitreous injection of 0.25 mg/L BBG, the number of viable RGCs was not affected. The number of viable RGCs showed a tendency to decrease in the 2.5-mg/L group 14 days after the injection, but the difference was not significant compared with the number in the saline-treated control group. Conclusion: Brilliant Blue G exerts no detectable detrimental effect on RGCs after short-time exposure, and no significant toxic effect even after a longer-time exposure in the current experimental setting. We have investigated the effects of Brilliant Blue G on rat retinal ganglion cells, both in vitro and in vivo. Our study clearly demonstrated that although Brilliant Blue G is toxic to retinal ganglion cells, Brilliant Blue G was less toxic than indocyanine green at the same concentration and exposure time in the current experimental setting.