Free Radical Scavenger Edaravone Research Articles

Pretreatment with edaravone reduces lung mitochondrial damage in an infant rabbit ischemia-reperfusion model

Purpose Free radical scavenger edaravone has been approved as a new drug for treatment of stroke patients. The purpose of this study was to examine whether pretreatment with edaravone could attenuate ischemia-reperfusion (IR)–induced lung damage in infant rabbits. Methods New Zealand White rabbits (Experimental Animal Center, Nanjing Medical University, Nanjing, China) at age from 15 to 21 days were subjected to sham operation, IR, or edaravone plus IR. Ischemia/reperfusion was induced by clamping the right pulmonary hilum for 1 hour and then removal of the clamp for 4 hours. Edaravone (1 mg/kg, intravenous) was given 5 minutes before ischemia. Concentrations of reactive oxygen species-hydroxyl radical (ROS-HR) and malondialdehyde (MDA), and activities of glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) in the lung tissue were measured. Mitochondrial membrane potential, swelling rate, and ultrastructure of the lung were analyzed, and histologic condition of the lung was evaluated. Results Edaravone pretreatment reduced markedly the productions of ROS-HR and MDA and increased the activities of GSH-PX and SOD. It attenuated both IR-induced decrease in mitochondrial membrane potential from 60% to 14% and IR-induced increase in mitochondrial swelling. As results, the mitochondrial and lung tissue damages were less, leading to an improved survival rate in IR rabbits pretreated with edaravone compared with IR rabbits without the treatment. Conclusion Edaravone pretreatment reduces the IR-induced lung mitochondrial damage in infant rabbits.

Free Radical Scavenger (Edaravone) Blocks Fas-Induced Apoptosis Pathway in Mice

Free Radical Scavenger (Edaravone) Blocks Fas-Induced Apoptosis Pathway in Mice

シンポジウム１‐３ 脳血管障害：基礎と臨床の最前線 画期的治療技術の開拓：脳保護療法から遺伝子・再生治療まで

A free radical scavenger Edaravone is the first clinical drug for neuroprotection in the world which has been used from 2001 in most ischemic stroke patients in Japan, and is especially useful in thrombolytic therapy with tissue plasminogen activator (tPA). Of great importance for regenerative therapy and gene therapy are the neural stem cells which are intrinsically activated or exogenously transplanted. Addition of NTFs greatly enhanced an intrinsic migration or invasion of stem cells into the scaffold, which could provide a future regenerative potential against ischemic brain damage at chronic stage.

Administration of Free Radical Scavenger Edaravone Associated With Higher Frequency of Hemorrhagic Transformation in Patients With Cardiogenic Embolism

Free radicals are known to activate coagulation and inhibit fibrinolysis. Edaravone, a free radical scavenger, protects vascular endothelial cells and neurons during acute brain ischemia in in vitro models. Hemorrhagic transformation and treatment outcomes were retrospectively examined in 76 patients with acute cardiogenic embolism treated with edaravone in addition to routine treatment within 24 hours of the onset of symptoms. Hemorrhagic transformation was categorized according to European Cooperative Acute Stroke Study-II. Patient characteristics were also evaluated, including evidence of hypertension, diabetes mellitus, hyperlipidemia, coronary heart disease, history of smoking, National Institutes of Health Stroke Scale on arrival, and modified Rankin scale at 3 months post-onset. Edaravone administration was one of the factors that contributed to increased frequency of hemorrhagic transformation, but had showed no significant relationship with the outcome. The present study showed that edaravone administration increased the frequency of hemorrhagic transformation with heparin in patients with cardiogenic embolism. Free radical scavenging may have promoted the coagulating conditions. Edaravone administration may allow reduction of the dose of heparin and tissue plasminogen activator in patients with acute ischemic stroke.

Edaravone (MCI-186) Scavenges Reactive Oxygen Species and Ameliorates Tissue Damage in the Murine Spinal Cord Injury Model

The present study evaluated the effect of the free radical scavenger edaravone on lesion volume and neurological dysfunction after spinal cord injury (SCI) in mice, and investigated its protective effects on superoxide generation. Female C57BL/6 mice were subjected to SCI using a pneumatic impact device and were treated with 3 mg/kg of edaravone or vehicle 30 minutes before the insult. Motor functions were quantitatively evaluated. Lesion volume was assessed by Dohrmann's two-cone method after one week. In situ detection of superoxide in the injured cord was carried out using the superoxide-sensitive dye dihydroethidium (DHE) staining technique. Pretreatment with edaravone significantly improved motor dysfunction and reduced the lesion volume to about 63% of the control (p < 0.05). Semi-quantitative measurements of red fluorescence emitted from DHE revealed that the superoxide concentration increased in the lesion periphery at 1 and 3 hours after the insult, and that pretreatment with edaravone significantly inhibited the increase of superoxide concentration in the lesion periphery at both time points (p < 0.0001). Double staining with DHE and monoclonal antibody against MAP2 showed that most cells positive for DHE were also positive for MAP2. These findings suggest that edaravone ameliorates tissue damage by scavenging reactive oxygen species, especially in the neurons, after SCI.

Edaravone neuroprotection effected by suppressing the gene expression of the Fas signal pathway following transient focal ischemia in rats

Preclinical and clinical studies have demonstrated that a free radical scavenger edaravone has neuroprotective effects on ischemic stroke but the underlying mechanism is not fully understood. The aim of this research is to explore the effect of edaravone on the apoptotic process involving the Fas/FasL signaling pathway. Transient focal ischemia in rats was induced for 2 hours by middle cerebral artery occlusion (MCAO). After reperfusion rats were treated i.v. with either edaravone or physiological saline. The expression of Fas-associated death domain protein (FADD), death-associated protein (Daxx) and caspase-8 was examined by immunohistochemistry. The mRNA levels for FADD and Daxx by reverse-transcriptase PCR (RT-PCR) and apoptosis was assessed by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL). Neurological scores and infarction volumes were also evaluated. Edaravone significantly improved the neurological outcome (p<0.05) and reduced the total infarct volumes (p<0.05), compared with saline control. In addition, edaravone-treatment significantly reduced the number of TUNEL-positive cells (p<0.01), reduced expression levels of FADD, Daxx and caspase-8 immunoreactivity (p <0.05 approximately 0.01), and decreased mRNA levels of FADD and Daxx (p<0.05 approximately 0.01) within the peri-infarct area. We conclude that edaravone may protect ischemic neurons from apoptosis via suppressing the gene expression of the Fas/FasL signaling pathway.

Suppression of postoperative intimal hyperplasia of vein grafts with edaravone in rat models - a scanning electron microscope study.

Postoperative intimal hyperplasia, the most common cause of vein graft occlusion, is initiated by endothelial injury. In the present study, the mechanism by which the free radical scavenger edaravone (Radicut, Mitsubishi Tanabe Pharma Co, Japan) protects against endothelial injury in postoperative intimal hyperplasia was investigated. In 18 male Lewis rats, a right epigastric vein graft was interposed into the common femoral artery. Nine rats received a pre-operative intraperitoneal administration of edaravone (3.0 mg/kg, edaravone group) and the other nine rats received an equal volume of saline (saline group). After 1 h, five vein grafts from each group were treated with Verhoeff-van Gieson elastica stain and subjected to a histological examination. The other four vein grafts from each group were examined with an S-800 Hitachi scanning electron microscope (SEM) (Hitachi High-Technologies Co, Japan) at ×1000 magnification, as were three unoperated right epigastric veins (unoperated vein group). The endothelial areas of the vein grafts were measured using computerized planimetry of the SEM images (ImageJ version 1.37, National Institutes of Health, USA). The mean endothelial areas (%) were compared between the two groups. Verhoeff-van Gieson elastica stain revealed no significant differences between the two groups. SEM showed that endothelial cells in the unoperated epigastric vein had a cobblestone-like appearance. In the saline group, the endothelial cells were comb-shaped and had adherent monocytes. In the edaravone group, however, the cobblestone-like appearance of endothelial cells was well preserved, with little monocyte adhesion. Moreover, the mean (± standard error of the mean) endothelial area was significantly higher in vein grafts from the edaravone group than in those from the saline group (74±1.8% versus 56±4.3%, P<0.05), and was similar to those in the unoperated epigastric veins (72±1.9%). These findings show that endothelial injury is present soon after placement of the interposition graft. The authors believe that edaravone suppresses postoperative intimal hyperplasia by alleviating endothelial injury.

Effects of free radical scavenger on acute liver injury induced by d‐galactosamine and lipopolysaccharide in rats

Acute severe liver injury still has a high mortality rate. Acute liver injury induced by a coadministration of d-galactosamine (GalN) and lipopolysaccharide (LPS) is an experimental model of fulminant hepatitis in rats. Our aim is to investigate the effects of free radical scavenger on the injury induced by GalN/LPS in rats. Free radical scavenger edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) was twice injected into rats 5 min before and 60 min after the GalN/LPS injection. Liver injury was biochemically and histologically assessed. The survival rate was examined 72 h after the intoxication. In the GalN/LPS-treated rats, a marked elevation in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels was observed. On the other hand, edaravone significantly inhibited the elevation in serum AST and ALT levels. The efficacy of edaravone was also confirmedby histological analysis. Edaravone lowered the levels of proinflammatory cytokines TNF-alpha mRNA and interleukin-6 mRNA expression, antioxidative enzyme heme oxygenase-1 protein and myeloperoxidase activity, a marker of neutrophil infiltration, in rat livers. In addition, edaravone reduced the mortality rate in GalN/LPS-treated rats as compared to the rats without edaravone treatment. Free radical scavenger edaravone effectively ameliorated the liver injury induced by the GalN/LPS administration in rats, not only by attenuating oxidative stress, but also by reducing the expression of proinflammatory cytokines.

The free-radical scavenger edaravone restores the differentiation of human neural precursor cells after radiation-induced oxidative stress

Recently, it has been elucidated that cognitive dysfunction following cranial radiotherapy might be linked to the oxidative stress-induced impairment of hippocampal neurogenesis that is mediated by proliferating neural stem or progenitor cells. The novel free-radical scavenger edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has been clinically used to reduce neuronal damage following ischemic stroke. Here, we demonstrate via in vitro studies that edaravone protects human neural stem cells (NSCs) from cell death and restores their differentiation ability after irradiation; however, the protective effect of edaravone is not observed in human brain tumor cells. Our study may shed some light on the beneficial effects of free-radical scavengers in impaired neurogenesis following cranial radiation therapy.

Edaravone suppresses postoperative reperfusion injury in rat lower extremity: An immunohistological study.

The present study evaluated whether the free radical scavenger edaravone (Radicut [Mitsubishi Pharma Co, Japan]) can suppress lower extremity postoperative reperfusion injury by evaluating muscle cell viability with immunohistological stain (cytochrome c oxidase stain). Eight Lewis male rats (460 g to 510 g) were divided into two groups. In the control group, postoperative reperfusion injury models were created by clamping the bilateral common femoral arteries for 5 h and then releasing. In the other group, 9.0 mg/kg of edaravone was administered before clamping the bilateral common femoral arteries. After 5 h of reperfusion, the bilateral triceps muscles in both groups were stained with cytochrome c oxidase stain (each n=4 × 2). The positive areas of cytochrome c oxidase stain were measured and compared, using computerized densitometry (National Institutes of Health Image program, version 1.61). In the control group, the lower triceps muscles were not stained with cytochrome c oxidase. In the edaravone group, the lower triceps muscles were strongly stained with cytochrome c oxidase. The positive areas of cytochrome c oxidase stain were significantly greater in the edaravone group (133,000±12,000 μ(2)/mm(2), P<0.01) compared with the control group (8000±1300 μ(2)/mm(2)). The present study suggests that the preoperative administration of 9.0 mg/kg of edaravone may suppress postoperative reperfusion injury in a rat model.

Free Radical Scavenger Edaravone Suppresses X-ray-induced Apoptosis through p53 Inhibition in MOLT-4 Cells

Edaravone, a clinical drug used widely for the treatment of acute cerebral infarction, is reported to scavenge free radicals. In the present study, we investigated the radioprotective effect of edaravone on X-ray-induced apoptosis in MOLT-4 cells. Apoptosis was determined by the dye exclusion test, Annexin V binding assay, cleavage of caspase, and DNA fragmentation. We found that edaravone significantly suppressed the X-ray-induced apoptosis. The amount of intracellular ROS production was determined by the chloromethyl-2',7'-dichlorodihydro-fluorescein diacetate system. We found that the intracellular ROS production by X-irradiation was completely suppressed by the addition of edaravone. The accumulation and phosphorylation of p53 and the expression of p21(WAF1), a target protein of p53, which were induced by X-irradiation, were also suppressed by adding edaravone. We conclude that the free radical scavenger edaravone suppresses X-ray-induced apoptosis in MOLT-4 cells by inhibiting p53.

Cardioprotective Effect of Edaravone against Ischaemia–Reperfusion Injury in the Rabbit Heart Before, during and after Reperfusion Treatment

The free radical scavenger edaravone is able to stimulate prostacyclin release and inhibit the lipoxygenase pathway in the arachidonic acid cascade. The effect of edaravone administration on myocardial damage in rabbit hearts subjected to ischaemia-reperfusion was examined at different times relative to reperfusion. All rabbits underwent sustained coronary artery occlusion for 30 min followed by 3 h of reperfusion. Rabbits were divided into the following groups: control; early (3 mg/kg edaravone IV 10 min before reperfusion); immediate (3 mg/kg edaravone IV immediately after the start of reperfusion); and late (3, 6 or 10 mg/kg edaravone IV 5 min after the start of reperfusion). Single bolus administration of edaravone 10 min before reperfusion or immediately upon initiation of reperfusion appears to be associated with reductions in infarction size and the percentage of apoptotic cells, but treatment with edaravone 5 min after initiation of reperfusion does not appear to have this protective effect.

Edaravone (3-Methyl-1-Phenyl-2-Pyrazolin-5-one), A Novel Free Radical Scavenger, for Treatment of Cardiovascular Diseases

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a strong novel free radical scavenger, is used for treatment of patients with acute brain infarction. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Antioxidant actions of edaravone include enhancement of prostacyclin production, inhibition of lipoxygenase metabolism of arachidonic acid by trapping hydroxyl radicals, inhibition of alloxan-induced lipid peroxidation, and quenching of active oxygen, leading to protection of various cells, such as endothelial cells, against damage by reactive oxygen species (ROS). Recently, we have shown that edaravone improves endothelial function through a decrease in ROS in smokers. From a clinical perspective, it is important to select an appropriate drug that is effective in improving endothelial function in patients with cardiovascular diseases. The novel free radical scavenger edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, chronic heart failure, diabetes mellitus, or hypertension. This review focuses on clinical findings and on putative mechanisms underlying the beneficial effects of the antioxidative agent edaravone on the artherosclerotic process in patients with cardiovascular diseases.

内耳保護機構の解明と臨床応用

It is believed that the sensory cells are very fragile and that their function is difficult to recover after damage to the inner ear. Therefore, methods used for the protection of inner ear tissue against stress are important. We have studied the mechanism of hair cell protection. The review inculdes our recent studies on hair cell protection with clinical reagents. The effect of the free radical scavenger edaravone on acoustic trauma was investigated. Our results showed that edaravone could protect cochlear function against intense noise. The protective effects of the reagents tested were observed in the inner ear 9-21 hours after noise exposure. These results were supported by immunohistochemical analysis of 4-hydroxy-2-nonenal. An inducer of heat shock protein, teprenone, was used for cochlear protection. Western blot analysis showed that the expressions of Hsp70, 40, and 27 were increased 24-48 hours after the administration of a single dose of teprenone. In addition, daily administration of teprenone for 7 days could enhance Hsps expression more strongly than single dose administration. In test animals given teprenone before intense sound exposure, their ABR threshold elevations were lowered significantly. In addition, significantly fewer defects were observed in outer hair cells of the organ of Corti in animals treated with teprenone than in those of non-teprenone-treated animals.These clinical reagents are candidates for cochlear protection therapy.

Protective effect of the free radical scavenger (edaravone) against the photochemically induced cerebral infarction in the mice

Protective effect of the free radical scavenger (edaravone) against the photochemically induced cerebral infarction in the mice

Temporal effects of edaravone, a free radical scavenger, on transient ischemia-induced neuronal dysfunction in the rat hippocampus

We examined the effect of a free radical scavenger edaravone on ischemia/reperfusion-induced impairment of long-term potentiation in the perforant path-dentate gyrus synapses of the rat hippocampus, as a measure of functional outcome 4 days after transient global ischemia (2-vessel occlusion, 10 min). Edaravone (3 and 10 mg/kg, i.v.) immediately after reperfusion (Day 0) alleviated ischemia-induced impairment of long-term potentiation in a dose-related manner, whereas treatment on Day 1 or 4 after reperfusion failed to rescue the impaired long-term potentiation. Edaravone administration on Day 0 also prevented the post-ischemic increase in hydroxyl radical formation and the expression of vascular endothelial growth factor, basic fibroblast growth factor and neuronal and inducible nitric oxide synthases of the hippocampus. Thus, edaravone protected the rat hippocampus from ischemia-induced long-term potentiation impairment with a therapeutic time window, suggesting that free radical formation after ischemia/reperfusion is a pivotal trigger of neurofunctional complications after global ischemic stroke.

頚部頚動脈内膜剥離術後過潅流―その病態・意義・対策・診断・予知―

We review cerebral hyperperfusion following carotid endarterectomy (CEA). Persistence of cerebral hyperperfusion greater than several days after CEA is associated with development of hyperperfusion syndrome. Postoperative cerebral hyperperfusion, even when asymptomatic, is associated with impairment of cognitive function in patients undergoing CEA. Further, development of hyperperfusion syndrome is associated with persistent postoperative cognitive impairment. Pretreatment with a novel free radical scavenger—edaravone—prevents occurrence of cerebral hyperperfusion itself after CEA. Intraoperative monitoring of transcranial regional cerebral oxygen saturation using near-infrared spectroscopy or monitoring of intraoperative middle cerebral artery blood flow velocity using transcranial Doppler ultrasonography identifies patients at risk for hyperperfusion after CEA. Reduced preoperative cerebrovascular reactivity to acetazolamide is a significant independent predictor of post-CEA hyperperfusion.

The radical scavenger edaravone prevents oxidative neurotoxicity induced by peroxynitrite and activated microglia

The free radical scavenger edaravone has been used as an anti-oxidative agent in acute ischemic brain disorders. We examined the effect of edaravone on the production of nitric oxide (NO), reactive oxygen species (ROS) and proinflammatory cytokines by activated microglia, and we also examined its neuroprotective role in cortical neuronal cultures oxidatively stressed by the peroxynitrite donor N-morpholinosydnonimine (SIN-1) or activated microglia. Edaravone significantly suppressed the production of NO and ROS by activated microglia, though it did not suppress production of inflammatory cytokines. In addition, edaravone significantly suppressed neuronal cell death and dendrotoxicity induced by either SIN-1 or activated microglia in a dose-dependent manner. These results suggest that edaravone may function as a neuroprotective agent counteracting oxidative neurotoxicity arising from activated microglia, as occurs in either inflammatory or neurodegenerative disorders of the central nervous system.

Neuroprotective effects of the free radical scavenger Edaravone (MCI-186) in mice permanent focal brain ischemia

The present study was aimed to evaluate the effect of the free radical scavenger Edaravone on infarct volume due to permanent MCA occlusion in mice and, if so, to elucidate the mechanism of its neuroprotective effects. Male Balb/c mice were subjected to permanent middle cerebral artery occlusion and were treated with 3.0 mg/kg of Edaravone or vehicle 30 min before ischemia. Infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride (TTC) method after 24 h. Furthermore, in situ detection of superoxide in the ipsilateral neocortex was carried out using the superoxide-sensitive dye dihydroethidium (DHE) staining technique. Pretreatment with 3.0 mg/kg of Edaravone ameliorated the tissue damage in the infarct rim and significantly reduced infarct volume to about 77% of the control ( p<0.05). Semi-quantitative measurement of red fluorescence emitted from DHE revealed that the superoxide increased in the ischemic core at 1 h after the onset of ischemia and extended towards the infarct rim at 3 and 6 h, and that pretreatment with 3.0 mg/kg of Edaravone significantly inhibited the increase of superoxide in the infarct rim at 3 and 6 h ( p<0.01). Double staining with DHE and monoclonal antibody against NeuN showed that the majority of the nuclei positive for DHE were also positive for NeuN. These findings suggest that Edaravone salvages the boundary zone of infarct by scavenging reactive oxygen species especially in the neurons during permanent focal cerebral ischemia.

Pretreatment with the Free Radical Scavenger Edaravone Prevents Cerebral Hyperperfusion after Carotid Endarterectomy

Cerebral hyperperfusion syndrome after carotid endarterectomy (CEA) is a rare but potentially devastating complication. The purpose of the present study, which was not a randomized controlled trial but a case cohort study with historical control, was to determine whether pretreatment with a novel free radical scavenger, edaravone, could prevent occurrence of cerebral hyperperfusion after CEA. Fifty patients with ipsilateral internal carotid artery stenosis (>/=70%) underwent CEA with administration of edaravone before internal carotid artery clamping. Preoperative cerebral blood flow and cerebrovascular reactivity (CVR) to acetazolamide were assessed with single-photon emission computed tomography (SPECT). Cerebral blood flow also was measured immediately after CEA and on the 3rd postoperative day. Cerebral hyperperfusion (cerebral blood flow increase >/=100% compared with preoperative values) was revealed by SPECT performed immediately after CEA in only one patient (2%), who also exhibited reduced preoperative CVR. The incidence of post-CEA hyperperfusion as revealed by SPECT in the control group (51 CEA patients without administration of edaravone) was significantly higher (16%) (P = 0.0310, control versus treatment group). In addition, in a subgroup of patients with reduced preoperative CVR, the incidence of post-CEA hyperperfusion as revealed by SPECT in the edaravone group (7%) was significantly lower than that in the control group (67%) (P = 0.0029). Logistic regression analysis demonstrated that reduced preoperative CVR and absence of pretreatment with edaravone were significant independent predictors of post-CEA hyperperfusion as revealed by SPECT. Pretreatment with edaravone can prevent occurrence of cerebral hyperperfusion after CEA.