Indocyanine Green induces apoptosis in Retinal Ganglion Cells

Abstract

Abstract: : Purpose: To evaluate the potential cytotoxic effects of Indocyanine Green on retinal ganglion cells (RGC) Methods: A transfected rat retinal ganglion cell–line (RGC–5) was exposed to ICG concentrations of 0.01 to 1.0 mg/mL for 10, 30 and 60 minutes. RGCs were examined for apoptosis, a form of cell death characterized by chromatin condensation, DNA degradation, and phosphatidylserine (PS) externalization. Cell morphology was evaluated with light–microscopy and cell counts and viability were assessed with flow cytometry. Cells were isolated and resuspended in 1 X binding buffer, and incubated with 5 µl of Annexin–V–FITC for 15 min at room temperature. DNA integrity was examined with propidium iodide counterstain. Results: The RGCs incubated for 10 minutes exhibited minimal morphological change compared to the control. When RGCs were exposed to 20 or 30 minutes of ICG 0.01, 0.1, and 1 mg/ml concentrations, the morphological features were altered and phosphatidylserine pick–up by Annexin–V increased significantly. (P<0.01) Table 1. Increased number of apoptotic cells on exposure to ICG 

Conclusion:Indocyanine green is cytotoxic to cultured RGCs in a dose and time dependent manner. Prolonged exposure of retina to ICG should be avoided during vitreoretinal surgery.

Keywords: retina • apoptosis/cell death