The effect of indocyanine green on cultured retinal glial cells
Masatoshi Murata1, Shinji Shimizu, Saburo Horiuchi
1Mitake Eye Clinic, Morioka, Japan. mitake@eins.rnac.ne.jp
Background:
Recently, indocyanine green (ICG) has been utilized to visualize inner limiting membrane in vitreous surgery. However, the safety of ICG injected into the vitreous has not been well established. The possible toxicity of ICG on Muller cells was investigated using cultured rat retinal glial cells (RGCs).
Methods:
Rat RGCs were cultured in Dulbecco modified Eagle medium supplemented with 20% fetal calf serum. The cytotoxicity of ICG was assayed with viable cell number and resazurin metabolic assay. The expression of the apoptosis-related gene bcl-2 was examined with real-time polymerase chain reaction analysis.
Results:
The effects of ICG on the viability of rat RGCs were tested at two different concentrations (0.05% and 0.5%). ICG significantly decreased the viable cell number of RGCs at 0.5%, while there was no significant effect at 0.05%. Similarly, the metabolic activity to resazurin was significantly decreased by exposure to 0.5% ICG. However, ICG showed little effects on resazurin metabolism at 0.05%. The expression levels of bcl-2 mRNA were higher in cells treated with 0.5% ICG than in those treated with 0.05% ICG and untreated control cells.
Conclusion:
The data suggest that ICG initiates the death of RGCs at high concentrations, in part, through apoptosis-related signal pathways.
Insights
High concentrations of indocyanine green (ICG) can harm Muller cells, a type of retinal glial cell, potentially through apoptosis. Lower concentrations appear safe for these cells in vitro, suggesting careful use in ophthalmic procedures.
Area of Science:
- Ophthalmology
- Cell Biology
- Toxicology
Background:
- Indocyanine green (ICG) is used in vitreous surgery for visualizing the inner limiting membrane.
- The safety of intraocular indocyanine green (ICG) injections remains under investigation.
- Muller cells are crucial retinal glial cells whose response to ICG is not fully understood.
Purpose of the Study:
- To investigate the potential toxicity of indocyanine green (ICG) on Muller cells.
- To assess the impact of different ICG concentrations on retinal glial cell viability and function.
Main Methods:
- Cultured rat retinal glial cells (RGCs) were utilized for in vitro experiments.
- Cytotoxicity was evaluated using viable cell counts and resazurin metabolic assays.
- Apoptosis-related gene bcl-2 expression was analyzed via real-time polymerase chain reaction.
Main Results:
- Indocyanine green (ICG) at 0.5% significantly reduced RGC viability and metabolic activity.
- A lower concentration of 0.05% indocyanine green (ICG) showed no significant cytotoxic effects.
- Increased expression of the apoptosis marker bcl-2 was observed at the higher ICG concentration.
Conclusions:
- Indocyanine green (ICG) can induce Muller cell death at high concentrations.
- Apoptosis-related signaling pathways may mediate the toxicity of indocyanine green (ICG).
- These findings highlight the importance of ICG concentration in ophthalmic applications.
