Abstract
Purpose: :
Vital dyes such as infracyanine green (IfCG), brilliant blue green (BBG) and bromophenol blue (BPB) have been used as an alternative to Indocyanine green (ICG) during chromovitrectomy. We evaluated the invitro toxicity of IfCG, BBG, BPB with ICG on the retinal pigment epithelium (RPE) and retinal ganglion cell (RGC) at various concentrations to optimize the safe dose and duration of exposure.
Methods: :
Cultured rat retinal ganglion cells (RGC-5) and human RPE (ARPE-19), were exposed to two concentrations (0.25 and 0.5 mg/ml) of ICG, IfCG, BBG and BPB at various time intervals (1, 5, 15 and 30 minutes). Cell viability was quantified with neutral red (NR) assay and mode of cell death was evaluated with flow cytometry based Annexin-V and propidium iodide (PI) staining. Phase contrast bright field microscopy was used to identify structural morphology. All measurements were repeated thrice to check concordance.
Results: :
Exposure to ICG resulted in 48-74% reduction in NR uptake in both RGC-5 and ARP-19, after exposure time of 5 minutes or greater, compared to control (p<0.001). IfCG and BBG were significantly less toxic when compared to ICG on the two cell lines at exposure times less than 15 and 30 minutes, respectively (Reduction in cell viability ranged from 6.9 + 3.3 % to 29.3 + 7.4 % when compared to control, p>0.5) . Cells exposed to BPB did not reveal any significant decrease in NR uptake at both the concentrations tested for the exposure times tested in the study. These results were supported by flow cytometry studies of Annexin and PI stained cells.
Conclusions: :
Newer vital dyes, IfCG, BBG and BPB are significantly less toxic on RGC and RPE cell lines when compared to ICG. BPB was least toxic among the three newer dyes studied.
Keywords: vitreoretinal surgery • macular holes • retinal culture