Abstract
Purpose: :
To evaluate the toxicity of Brilliant Blue G (BBG) with and without light (L) on Müller cells (MIO-M1) in vitro.
Methods: :
MIO-M1 cells (courtesy of A. Limb) were treated with one of three different concentrations of BBG 0.0125mg/ml (0.5x clinical concentration), 0.25mg/ml (1x), or 0.5mg/mg (2x) with or without halogen light (Pilling Surgical, Model#529317) of 3000 lux exposure for 10, 15, or 30 minutes. The dye-exclusion trypan blue cell viability (CV), caspase-3/7 activity, and JC-1 assays were used to measure change in CV, apoptosis, and mitochondrial membrane potential (ΔΨm) respectively at 24 hours.
Results: :
All tested concentrations of BBG with or without light (2x+L, 2x, 1x+L, 1x, 0.5x+L, 0.5x or L) for 30 minutes were found to be safe on MIO-M1 cells when using the cell viability and caspase-3/7 activity assays. The mean % CV of MIO-M1 cells after BBG treatment with or without light for 30 min were 92.5±0.5 (p>0.05), 92.5±1.3 (p>0.05), 93.1±0.9 (p>0.05), 94.9±0.9 (p>0.05), 94.6±0.6 (p>0.05), 94.5±0.9(p>0.05), 96±1 (p>0.05) for 2x+L, 2x, 1x+L,1x, 0.5x+L, 0.5x, and L respectively compared to untreated MIO-M1 control cells (96±2). Caspase-3/7 activity was not increased significantly after BBG treatment with or without light in MIO-M1 cells compared to untreated MIO-M1 control cells. ΔΨm in MIO-M1 cells was reduced significantly only at 2x+L and 2x compared to untreated control cells: 9.9±0.5 (p<0.01) for 2x+L and 11.2±0.2 (p<0.05) for 2x compared to 14.9±0.6 in untreated MIO-M1 control cells. At lower doses ΔΨm values were not significantly reduced. ΔΨm values for 1x+L,1x, 0.5x+L, 0.5x, or L were12.4±0.5 (p>0.05), 13.2±0.2 (p>0.05), 13.7±0.2 (p>0.05), 14.3±0.5 (p>0.05) , and 14.3±0.5 (p>0.05) compared to 14.9±0.6 in untreated MIO-M1 control cells.
Conclusions: :
In this study, exposure of human retinal Muller cells in culture to clinically utilized concentrations of vital dye Brilliant Blue G and light for up to 30 minutes did not decrease cell viability, or cause apoptosis or mitochondrial damage. However when twice the clinical dose with or without light was utilized for 30 minutes, mitochondrial damage was observed, though no decrease in cell viability or apoptosis was noted. Brilliant Blue G appears to be relatively safe to retinal cells in culture compared to other vital dyes such as trypan blue and indocyanine green.
Keywords: Muller cells • drug toxicity/drug effects • cell survival