title: Edaravone, a free radical scavenger, protects against retinal damage in vitro and in vivo.
abstract: 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 H(2)O(2), superoxide anion (O(2)*), 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 NH(2)-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.
authors.affiliation: Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, Gifu, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Inokuchi
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Imai
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Nakajima
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Shimazawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Aihara
authors.forename: Makoto
authors.initials: M
authors.lastname: Araie
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hara
mesh_terms: D000818:Animals; D000983:Antipyrine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003470:Culture Media; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D000077553:Edaravone; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D005609:Free Radicals / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D016202:N-Methylaspartate; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D012164:Retinal Diseases / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018800:Thy-1 Antigens / Q000235:genetics
chemical_list: D003470:Culture Media; C485182:Cyan Fluorescent Protein; D016166:Free Radical Scavengers; D005609:Free Radicals; D018800:Thy-1 Antigens; D049452:Green Fluorescent Proteins; D016202:N-Methylaspartate; D000077553:Edaravone; D000983:Antipyrine