Effect Of Electroacupuncture Preconditioning On IRE1-XBP1 Signaling Pathway Of Rats With Cerebral Ischemia-reperfusion Injury

Objective: In this study,we use a mouse model of middle cerebral artery occlusion(MCAO)to mimic ischemia/reperfusion injury.Before cerebral ischemiareperfusion(I/R)they were subjected to repetitive electroacupuncture(EA)stimulation.And then to dectect the neurological deficit score,the Changes in cell morphology,ang the expression of IRE1-XBP1.To evaluate the effect of electroacupuncture preconditioning on IRE1-XBP1 signaling pathway of rats with cerebral ischemia-reperfusion(I/R)injury.To investigate the mechanism of electroacupuncture pretreatment by inhibiting endoplasmic reticulum stress to reduce cell apoptosis and to play a role in brain protection,and to provide a basis for clinical treatment of cerebral ischemia.Methods : One hundred and eight healthy male SD rats,aged 8-12 weeks,weighting200-250 g,were randomly assigned into 3 groups(n=36 each)using a random number table: sham operation group(group S),ischemia-reperfusion group(group I/R)and electroacupuncture preconditioning group(group EA).Focal cerebral I/R model was induced by occlusion of middle cerebral arteries for 2 h followed by reperfusion in rats anesthetized with chloral hydrate.In group S,the thread was inserted into the common carotid artery about 6 mm during the operation.In group S ang EA,the thread was inserted into the internal carotid artery about 18-20 mm during the operation.In group EA,electroacupuncture of Baihui acupoints lasting for 30 min was performed once a day for 5 consecutive days starting from 5 days before ischemia,and the model was established at 24 h after the last preconditioning.Twelve rats were randomly assigned into 3 subgroups to assessed neurological deficit score at 6 h,12 h and 24 h of reperfusion.The rats were then sacrificed,and brains were removed and cut into sections to observe the changes in ultrastructure by electronic microscope and theexpression levels of IRE1 and XBP1 proteins detected by Western blot at 6 h,12 h and24 h of reperfusion.Results:1.Neurological deficit score: Compared with the S group,the neurological deficit score in I/R group and EA group were significant increased at each time point of reperfusion,the difference was statisticallysignificant(P<0.01).Compared with the I/R group,the neurological deficit score in EA group were significant decreased at each time point of reperfusion,the difference was statisticallysignificant(P<0.05).2.The Changes in cell morphology: The cell morphology of ischemia in S group was normal under transmission electron microscope.The cells were edema at 6 h after reperfusion in I/R group.The cell damage was aggravated after 12 h reperfusion.At 24 h,the neuronal volume was reduced,and there was more space between the cells.Cytoplasm reduced or even disappeared,endoplasmic reticulum pool,most of the nuclear membrane broken defect,nuclear contents spillover into the cytoplasm,chromatin pyknosis,edge set clear,endothelial cell swelling is severe,more diffuse swelling of the endothelial cells into,fall off,nucleus pycnosis,glial cell necrosis,chromatin condensed into small pieces and edema of cytoplasm and organelles,rough endoplasmic reticulum expansion into capsule pool shape,the nucleus degeneration swelling,foot process also see severe swelling;The cell damage was significantly reduced at each time point of EA group.3.Detected by western blot: Compared with the S group,the expression of IRE1-XBP1 in I/R group and EA group were significant increased at each time point of reperfusion,the difference was statisticallysignificant(P<0.01).Compared with the I/R group,the expression of IRE1-XBP1 in EA group were further increase at each time point of reperfusion,the difference was statisticallysignificant(P<0.05).Conclusion: 1.Electroacupuncture pretreatment can reduce neurological deficits of rats after cerebral ischemia reperfusion.2.Electroacupuncture pretreatment can improve the damage of cerebral ischemia cells in rats after cerebral ischemia reperfusion.3.Electroacupuncture could relieve the stress of endoplasmic reticulum,inhibit the apoptosis of nerve cells by increased the expression of IRE1 and XBP1 proteins,and thus play a role in brain protection.