| Objective:To research the effect of methylene blue(MB)pretreatment on focal cerebral ischemia-reperfusion(I/R)injury in rats and its possibly mechanism.Methods:Sixty-four adult male Sprague-Dawley rats were randomly divided into four groups(n=16):sham group(group S),methylene blue control group(group S+M),focal cerebral ischemia-reperfusion group(group I/R),methylene blue pretreatment group(group I/R+M).The rat model of focal cerebral ischemia-reperfusion was established by middle cerebral artery occlusion.The neurological deficit scores were performed with Longa’s scale at 5 min before reperfusion and at 24 h after reperfusion.The pathological changes in pallium of ischemic area were observed by HE staining.Reactive oxygen species(ROS)in ischemic brain tissue were measured by chemiluminescent.The expressions of nuclear factor erythroid 2-related factor 2(Nrf2)and heme oxygenase 1(HO-1)in ischemic brain tissue were detected by Western blot and immunohistochemistry staining.Results:The neurological deficit scores,the cerebral infarct volume and the infarct volume fraction,the content of ROS,the expression of Nrf2 and HO-1 were all obviously higher in group I/R and I/R+M than in group S and S+M respectively(P<0.01).The neurological deficit scores,the cerebral infarct volume and the infarct volume fraction,the content of ROS were all obviously lower in group I/R+M than in group I/R(P<0.01).The expressions of Nrf2 and HO-1 were obviously increased in group I/R+M than in group I/R(P<0.01).The pathological changes in pallium of ischemic area were significantly ameliorated in group I/R+M than in group I/R.The difference between group S and group S+M was not statistical significant(P>0.05).Conclusion:The pretreatment of methylene blue can improve the focal cerebral ischemia-reperfusion injury in rats,which might be related to upregulated the expression of Nrf2 and HO-1,reduce the content of ROS in brain,produce antioxidant stress. |
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