Purpose: Cyclosporine A (CSA) is a widely used immunosuppressive drug. Furthermore, CSA showed neuroprotective properties in several neurological disorders. However, nearly no data exist regarding CSA and its possible neuroprotective effect on retinal ganglion cells (RGCs).
Methods: RGC-5 cells were stressed with 10 mM glutamate for 24 hours with or without adding varying concentrations of CSA (1, 3, 6, or 9 μg/mL) to the medium. Cell viability and cell density were analyzed by MTS assay and crystal violet staining, respectively. Induction of apoptosis was determined through caspase 3/7 activity and Annexin V+/PI− flow cytometry.
Results: The incubation of RGC-5 cells with 10 mM glutamate for 24 hours induced a 3.1-fold and a 3.4-fold decrease in overall cell viability and cell density, respectively, compared with controls. The supplementation of 9 μg/mL CSA to 10 mM glutamate led to a 2.7-fold increase in overall cell viability (P<0.0005) and a 2.5-fold increase in cell density (P<0.0005) compared with RGC-5 cells treated only with 10 mM glutamate. Furthermore, the addition of 9 μg/mL CSA to 10 mM glutamate significantly reduced caspase 3/7 activity by 1.3-fold (P<0.0005) and the amount of Annexin V+/PI– cells by 2.8-fold compared with RGC-5 cells incubated with 10 mM glutamate alone. The neuroprotective effect of CSA dose-dependently decreased with lower concentrations.
Conclusions: CSA can effectively protect RGC-5 cells against glutamate-induced excitotoxicity. Therefore, CSA should be tested in further experiments to evaluate its potential as a neuroprotective substance against RGC disorders.
*Centre for Ophthalmology, University Eye Hospital Tübingen, Tübingen
†Department of Ophthalmology, Charite Berlin, Berlin, Germany
Disclosure: Supported by Deutsche Ophthalmologische Gesellschaft: Forschungsförderung der DOG für innovative wissenschaftliche Projekte in der Augenheilkunde. The authors declare no conflict of interest.
Reprints: Sven Schnichels, PhD, Centre for Ophthalmology, University Eye Hospital Tübingen, Schleichstr, 12/1, 72076 Tübingen, Germany (e-mail: email@example.com).
Received June 13, 2012
Accepted January 10, 2014