Abstract
Purpose: :
This study was to determine whether edible wild vegetable, Gymnaster koraiensis, is effective at blunting the negative influence of N-methyl-d-aspartate (NMDA) to the rat retina and of oxidative stress induced transformed retinal ganglion cells (RGC-5) death.
Methods: :
RGC-5 cells in culture were given negative insult such as l-buthionine-(S,R)-sulfoximine (BSO, 0.5 mM) plus glutamate (10 mM) for 24 hours, after which cell survival were tested. ROS quantification was performed by using the fluorescence probe, 2',7'-dichlorodihydrofluorescein diacetate (DCFH -DA), and glutathione level was tested based on the reaction of glutathione with 5,5’-dithio-bis(2-nitrobenzoic acid) (DTNB). Apoptotic cell death was measured by propidium iodide (PI)/Hoechst 33342 double staining and western blot analysis. NMDA-induced retinal damage in vivo was tested by hematoxylin-eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) staining. The amount of formation for thiobarbituric acid reactive species (TBARS) was used as the rate of membrane lipid peroxidation.
Results: :
The ethyl acetate fraction of G. koraiensis (EAGK) significantly attenuated the negative insult of BSO plus glutamate to RGC-5 cells. Treatment of the RGC-5 cells with EAGK reduced the reactive oxygen species (ROS) and recovered reduced glutathione level caused by various radical species such as H2O2, OH· or O2·–. Moreover, EAGK inhibited lipid peroxidation caused by sodium nitroprusside (SNP) to rat brain homogenates. NMDA to the retina affected the thickness of inner plexiform layer (IPL) and TUNEL positive ganglion cells. Importantly, EAGK protected the thinning of IPL and increased TUNEL positive cells in ganglion cell layer (GCL).
Conclusions: :
EAGK has neuroprotective effects in vitro and in vivo.
Keywords: neuroprotection • oxidation/oxidative or free radical damage • antioxidants