Edaravone, a Free Radical Scavenger, Protects against Retinal Damage in Vitro and in Vivo

• Published in: The Journal of pharmacology and experimental therapeutics 2009-05, Vol.329 (2), p.687-698
• Main Authors: Inokuchi, Yuta, Imai, Shunsuke, Nakajima, Yoshimi, Shimazawa, Masamitsu, Aihara, Makoto, Araie, Makoto, Hara, Hideaki
• Format: Article
• Language: English
• Subjects: Animals; Antipyrine - administration & dosage; Antipyrine - analogs & derivatives; Antipyrine - pharmacology; Antipyrine - therapeutic use; Cell Line; Cell Survival - drug effects; Culture Media; Disease Models, Animal; Dose-Response Relationship, Drug; Free Radical Scavengers - administration & dosage; Free Radical Scavengers - pharmacology; Free Radical Scavengers - therapeutic use; Free Radicals - metabolism; Green Fluorescent Proteins - genetics; Male; Mice; Mice, Transgenic; N-Methylaspartate; Oxidative Stress - drug effects; Rats; Retinal Diseases - genetics; Retinal Diseases - metabolism; Retinal Diseases - pathology; Retinal Diseases - prevention & control; Retinal Ganglion Cells - drug effects; Retinal Ganglion Cells - metabolism; Retinal Ganglion Cells - pathology; Thy-1 Antigens - genetics
• ISSN: 0022-3565; 1521-0103
• DOI: 10.1124/jpet.108.148676

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, is used for the treatment of acute cerebral infarction. In this study, we investigated whether edaravone is neuroprotective against retinal damage. In vitro, we used a radical-scavenging capacity assay using reactive oxygen species-sensitive probes to investigate the effects of edaravone on H2O2, superoxide anion (▪), and hydroxyl radical (·OH) production in a rat retinal ganglion cell line (RGC-5). The effect of edaravone on oxygen-glucose deprivation (OGD)-induced RGC-5 damage was evaluated using a 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt assay of cell viability. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) significantly decreased radical generation and reduced the cell death induced by OGD stress. In vivo, retinal damage was induced by intravitreous injection of N-methyl-d-aspartate (NMDA; 5 nmol) and was evaluated by examining ganglion cell layer cell loss, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining, and the expressions of two oxidant-stress markers [4-hydroxy-2-nonenal (4-HNE) and 8-hydroxy-2-deoxyguanosine (8-OHdG)]. In addition, activations of mitogen-activated protein kinases (MAPKs) [extracellular signal-regulated protein kinases (ERK), c-Jun NH2-terminal kinases (JNK), and p38 MAPK], as downstream signal pathways after NMDA receptor activation, were measured using immunoblotting and immunostaining. Edaravone at 5 and 50 nmol intravitreous injection or at 1 and 3 mg/kg i.v. significantly protected against NMDA-induced retinal cell death. At 50 nmol intravitreous injection, it 1) decreased the retinal expressions of TUNEL-positive cells, 4-HNE, and 8-OHdG and 2) reduced the retinal expressions of NMDA-induced phosphorylated JNK and phosphorylated p38 but not that of phosphorylated ERK. These findings suggest that oxidative stress plays a pivotal role in retinal damage and that edaravone may be a candidate for the effective treatment of retinal diseases.