Investigation Of The IRE1 Access XBP1, CHOP Gene Expression Following Cerebral Ischemia And Reperfusion In Rat And The Effects Of Shenxiong

Background and ObjectiveCerebral ischemia-reperfusion injury induced cell death,including apoptosis and cell death,delayed injury of the cerebral neurons in the form of apoptosis .Recent studies show that ischemic brain injury not only exists in the mitochondrial pathway and death receptor pathway but also exists in the endoplasmic reticulum pathway.Endoplasmic reticulum stress response, IRE1-mediated UPR signaling pathway is very important.IRE1-mediated signaling pathway not only induced the expression of XBP1, but also inducing apoptosis factors such as the expression of CHOP initiated apoptosis. XBP1 is endoplasmic reticulum stress signs.Presently,few studies on the IRE1-mediated UPR signaling pathway in the model of cerebral ischemia and reperfusion had been reported.In this work,we detected the expression development of XBP1,CHOP genes and explored the roles and association with brain damage after cerebral ischemia reperfusion in rats. Furthermore, the effects of shenxiong on related genes expression in IRE1 pathway were detected.Then the mechanism of neuroprotective effect produced by shenxiong were eluciateded,which provide us with new theory and method for clinical treatment of cer??l ischemia.MethodsThe 144 healthy male spraue-dawley rats were randomly divided into two group:sham operation group,cerebral ischemia model group in part 1. But in part 2, the 72 healthy male spraue-dawley rats were randomly divided into shenxiong treated group.Transient focal cerebral ischemia was induced by middle cerebral artery occlusion(MCAO)for 2 hours followed by reperfusion in the rat. Then, neurolgical behavior evaluation were evaluated by the methods of Longa's scoring. Reperfusion after 6 h, 12h, 24h, 72h rats were sacrificed. The cerebal infarction volume were evaluated by the methods of TTC staining.The expression of XBP1,CHOPmRNA and protein were measured with methods of reverse transcription polymerase chain reaction and immunohistochemistry. The neuronal apoptosis was detected by the method of terminal deoxynucleotidy1 transferase-mediated dUTP-biotin nick end labeling.Results1. Cerebral infarction volume and the apoptosis cell counting were increasing gradually after cerebral ischemia-reperfusion and reach a peak at 24h afer reperfusion.2.The expression of XBP1,CHOP were up-regulated in per-infarction after cerebral ischemia-reperfusion in rats.The expression level of XBP1 mRNA and protein reached a peak at 6h,12h after reperfusion, respectively; The expression level of CHOP mRNA and protein reached a peak at 12h,24h after reperfusion, respectively.3.Compared with the saline control group, treat with shenxiong could reduce the neuronal apoptosis and reduce neurological deficits at 12h,24h,72h af??reperfusion(P<0.05).4.Compared with the saline control group, treat with could decrease XBP1,CHOP mRNA and protein expression at 6h,12h, 24h,72h after reperfusion(P<0.01).Conclusions1.Cerebral ischemia reperfusion may induce ERS, Which initiate IRE1 mediated UPR signal pathway.2.CHOP expression development paralleled with the changes of the apoptosis cell counting after cerebral ischemia reperfusion in rats,which suggested that CHOP play a role in neuronal apoptosis.3.Shenxiong could reduce neurological deficits and cerebral infarction volume after cerebral ischemia reperfusion in rats. 4.Shenxiong could inhibit endoplasmic reticulum stress reaction and apoptosis signal pathway by the expressive down-regulation of XBP1,CHOP after cerebral ischemia reperfusion in rats,which may result in decreases of neuronal apoptosis and ischemical reperfusion injury.