Abstract
Purpose :
Trypan blue (TB) has been widely used in ocular clinical practice and research but its safety is still not known clearly. The aim of this study was to evaluate the efficacy and toxicity of various concentrations of trypan blue (TB) dye for staining during subretinal injection in rat eyes in vivo.
Methods :
Different concentrations (0.2%, 0.08%, 0.04% and 0.02%) of TB were injected subretinally in adult rats. PBS injection was applied for controls. The staining effect was observed by surgery microscopy in vivo. The injected eyes were cut into sections and the injected retina was observed under light microscopy. The retinal toxicity was measured by the terminal deoxynucleotidy1 transferase dUTP nick end labeling (TUNEL) and histology respectively. Electroretinography (ERG) was used to measure retinal function.
Results :
The areas were injected and seen immediately under surgical microscope in all concentrations TB groups and control groups. One day after the procedure, all subretinal blebs were flat. Under the surgical microscope, we saw the treatment area in the 0.2%, 0.08%, 0.04% TB groups but not in the 0.02% group. In the sections in 0.2%, 0.08% and 0.04% TB groups, the stained retina and scleral were seen under light microscope over 2 weeks. TUNEL+ cells appeared mainly in the outer nuclear layer (ONL), ganglion cell layer (GCL) and retinal pigment epithelium (RPE) layer at 1 day and 7 days after subretinal injection of 0.2% and 0.08% TB. Whereas rarely no TUNEL+ cells were found at the 0.04% TB group and PBS groups. The results of histologic evaluation were consistent with TUNEL detection. Two weeks after injection, the thickness of ONL in 0.2% TB group reduced significantly compared to that in 0.04% TB group and in PBS group. The thickness of ONL in 0.04% TB group and PBS group had no significant difference. The amplitude of B-waves in ERG after injecting 0.2% TB was significantly reduced when compared to 0.04% TB and PBS injection. The amplitude of B-waves in 0.04% TB group and in PBS group had no significant difference.
Conclusions :
In conclusion, TB induced neurotoxic effect on retinal cells in a dose-dependent manner. We found a relative safe and effective concentration (0.04%) of TB for subretinal injection staining which can facilitate for further investigations.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.