| Part one:The effectiveness of edaravone on the infarct size and neurological deficits after focal cerebral ischemia-reperfusion in ratsObjective:To investigate the effectiveness of edaravone (3-methyl- 1-phenyl-2-pyrazolin-5-one/MCI-186), a free radical scavenger , on the infarct size and neurological deficits after middle cerebral artery occlusion in ratbrain.Methods:Focal cerebral ischemia-reperfusion model was made by improved Longa's methods in male Sprague-Dawley rats( 250~300g), which were randomly separated into ischemia-reperfusion group and edaravone-treated group. Each group had 6 animals. The neurological deficits were evaluated in a posture test 24th after the ischemia-reperfusion. The brain was removed immediately and cut into six coronal slices (2mm in thickness) by a rat brain slicer. Each section was stained with the 2%TTC. The infarct size was measured by a computerized image analysis system, the behavioral evaluations and experiments were performed by different investigators in a double-blind fashion.Result:The mean scores were 3.0±0.64 and 1.5±0.5 in the ischemia-reperfusion group and the edaravone-treated group , respectively, at 24 hours after focal cerebral ischemia and reperfusion. The edaravone-treated group significantly(P < 0.01) improved the neurological deficits compared with the ischemia-reperfusion group. Compared with the ischemia-reperfusion group, the infarct size and the extent of cerebral edema was significantly(P < 0.01) reduced in the edaravone-treated group. Infarct size of caudate putamen were 46.1±6.3 mm in the ischemia-reperfusion group and 30.2±2.2 mm in the edaravone-treated group.Conclusions:Edaravone could reduce the infarct size and the extent of cerebral edema and improved the neurological deficits significantly after focal cerebral ischemia-reperfusion.Part two:The effectiveness of edaravone on APE/ Ref-1 and apoptosis after focal cerebral ischemia-reperfusion in ratsObjective:1.. To explore the effectiveness of edaravone on the histopathology of focal cerebral ischemia-reperfusion wth H.E staining method.2 To explore the variation of APE/ Ref-1 expression and apoptosis in the ischemic penumbra after the ischemia-reperfusion and the relationship between APE/ Ref-1 expression and apoptosis.3 To explore the effectiveness of edaravone on APE/ Ref-1 expression and apoptosis in the ischemic penumbra and its neuroprotection mechanism on brain ischemia.Methods:Focal cerebral ischemia-reperfusion model was made by improved Longa's method in male Sprague-Dawley rats. Animals were randomly separated into normal group , Sham-operation group ,ischemia-reperfusion group and edaravone-treated group. The ischemia-reperfusion group was separated into 6 subgroups, each group had 6 animals. The Sham-operation group and edaravone-treated group were killed at 24th and others experimental animals were killed at lth, 6th, 12th, 24th, 48th and 72th respectively after 2h of MCA occlusion and reperfusion. Anesthetized animals were perfused with 4% formaldehyde. Brains were removed and sectioned for H.E staining, APE/ Ref-1 immunohistochemical staining and POD staining of apoptosis neurons . The APE/ Ref-1 cells and POD-positive cells of each group were quantified.Result:H.E staining result suggested that edaravone could reduce the infarct size and the extent of cerebral edema after focal cerebral ischemia. Neurons edema, necrosis and destruction of histology in the ischemic penumbra were reduced significantly compared with the control.One hour after ischemia-reperfusion, very few APE/ Ref-1-negative cells were observed in the parietal cortex of putamen where there were mass APE/Ref-1-positive cells. The APE/Ref-1-positive cells were significantly decreased in the core of ischemia with the ischemia continuing. Region of ischemic penumbra contracted gradually, and the APE/Ref-1-positive cells decreased too , the number ofAPE/Ref-1-positive cells reached to the minimal at 72th. The quantity ofPOD-positive cells did not increase remarkably until 6 hours. However, they significantly increased 48 hours after ischemia. Compared with the control, the number of APE/Ref-1-positive cells increased significantly and POD-positive cells reduced significantly in ischemic penumbra in edaravone-treated group after 24 hours ischemia-reperfusion.Conclusions:Edaravone could reduce the infarct size, the extent of cerebral edema and destruction of histology after focal cerebral ischemia-reperfusion. APE/Ref-1 expression decreases in ischemic penumbra neurons after focal cerebral ischemia and that this reduction precedes apoptosis , and the neurons that lost APE/Ref-1 immunoreactivity became POD positive. Through upregulating the expression of APE/ Ref-1 protein, the free radical scavenger edaravone can improve the repair ability of brain tissue in the course of ischemic and mitigate the impairment of neurons and quantity of apoptosis in penumbra , thus preventing the extension of cerebral infarction. Our study suggests that edaravone could be a potent neuroprotector against brain ischemia injury by scavenging the free radical.
|
PDF Full Text Request