Electrophysiological effects of Brilliant Blue G in the model of the isolated perfused vertebrate retina

BACKGROUND: To facilitate epiretinal or inner limiting membrane peeling dyes like Indocyanine Green (ICG) as well as Trypan Blue (TB) were used so far. However, toxic effects on the retina were described for both dyes. The aim of our study was to investigate the retinal tolerance to the new dye Brilliant Blue G (BBG), which implies a possibly more favorable biocompatibility.

METHODS: Bovine retina preparations were perfused with an oxygen preequilibrated standard solution. The electroretinogram (ERG) was recorded using Ag/AgCl-electrodes. After recording stable b-wave amplitudes, Brilliant Blue G (BBG) was applied epiretinally for 10 s, 15 s, 30 s, 60 s and 120 s at a concentration of 0.25 mg/ml, which was recently proposed for vitreoretinal surgery. To disclose the effects of BBG on photoreceptor function two test series at the same concentration were performed to evaluate the impact of BBG on the a-wave amplitude. Aspartate at a concentration of 1 mM was added to the nutrient solution to obtain stable a-wave amplitudes. Thereafter, BBG was epiretinally applied for 30 s or 60 s. The recovery of the ERG-amplitudes was followed up for 115 min.

RESULTS: Reductions of the a- and b-wave amplitude were found directly after exposure with BBG in each test series, but the effects on the electroretinogram after application of BBG were rapidly and completely reversible within the recovery time for all exposure times. No differences were found between the ERG-amplitudes before and after dye application at the end of the washout.

CONCLUSIONS: BBG seems to be an alternative vital staining dye with a good biocompatibility. Comparing the effects with Indocyanine Green or Trypan Blue in the model of the isolated perfused vertebrate retina BBG exhibits a more favorable safety profile.