The Protective Effects Of Endoplasmic Reticulum Stress Preconditioning On Cerebral Ischemia-reperfusion Injury In Rat Hippocampal Neurons

ObjectiveWe used 2-deoxyglucose(2-DG)which could induce endoplasmic reticulum stress pretreat cerebral ischemia-reperfusion injury(I/R)rats,then observed hippocampal neuronal damage and the expression of ERS-related molecules GRP78,XBP-1.To discussion the protection of rat hippocampal neurons by ERS pretreatment and the possible mechanism.And we fond the optimal dose of 2-DG inducing endoplasmic reticulum stress.MethodsWe choosed 360 healthy adult male Sprague-Dawley(SD)rats Weighing 180-240g.These rats were divided into six groups:sham group,cerebral ischemia and reperfusion(I/R)group,2-DG 50mg/kg group,2-DG100mg/kg group,2-DG150mg/kg group,2-DG200mg/kg group,meantime we used different dosage of 2-DG to set up model of endoplasmic reticulum stress.Each group has five time points:3h,6h,12h,24h,48h.After reperfusion time rats were killed. 2-DG group were injected intraperitoneally once a day for a total of 7d.2-DG was dissolved in distilled water and its working concentration was 50mg/mL. Rats in 2-DG group were divided into four dose groups,respectively, in accordance with 50mg/kg,100mg/kg,150mg/kg,200mg/kg dose of intraperitoneal injection,day 1 for 7 days;I/R group and sham operation group received the same volume of distilled water instead of 2-DG,day 1 for 7 days. We record rats'neurological behavioral score after corresponding time points of reperfusion and then killed the rats.Detected the expression of GRP78 and XBP-1 by the methods of Nigeria dyeing, immunohistochemistry,RT-PCR and western blot.Results2-DG groups'scores are decreased compared with sham-operation and Ischemia-reperfusion group(P<0.01),the 2-DG 100mg/kg group decrease more obviously(P<0.05).2-DG groups could improve nerve cell damage,which could make cell membranes more clearly, form to be normal, and visible nucleole of nerve cells is increased.2-DG 100mg/kg group was the most significant.2-DG group's expression of GRP78 increased obviously and compared with Ischemia-reperfusion group, it is more obviously.(P<0.01). Furthermore, the expression of 2-DG100mg/kg group was increased most obviously compare to other 2-DG groups.2-DG100mg/kg groups'scores are decreased compared with sham-operation and Ischemia-reperfusion group (P<0.01),the 2-DG 100mg/kg12hgroup decrease more obviously (P<0.01).2-DG100mg/kggroups could improve nerve cell damage, which could make cell membranes more clearly, form to be normal, and visible nucleole of nerve cells is increased.2-DG 100mg/kg12hgroup was the most significant.2-DG 100mg/kg group's expression of GRP78 increased obviously and compared with Ischemia-reperfusion group,2-DG 100mg/kg12hgroup is more obviously.(P<0.01).Show that neurons hapen the endoplasmic reticulum stress,2-DG plays a role in the induction of ERS, suggesting that ERS pretreatment has a protective effect of hippocampal neurons; ERS pretreatment induced ischemic tolerance.Compared with the sham group, expression of GRP78 protein,XBP-1 protein in ischemia-reperfusion group and 2-DG100mg/kg group was significantly increased (P <0.01);Compared with ischemic reperfusion group, the expression of GRP78 protein,XBP-1 protein of 2-DG100mg / kg group was significantly increased (P<0.01),2-DG100mg /kg12hgroup was the highest expression group; Compared with the sham operation group, the expression of GRP78mRNA,XBP-1 mRNA in ischemia-reperfusion group and the 2-DG100mg/kg group was significantly increased(P<0.01);and Compared with ischemic reperfusion group, the expression of GRP78mRNA,XBP-1 mRNA of 2-DG100mg / kg group at each time point was significantly increased (P<0.01), 12h group was the highest expression; Show XBP-1-GRp78 ERS pathway activation may be an important protective effect of preconditioning mechanism.Conclusions1.2-DG can be successfully induced ERS pretreatment, the optimal dose may be 100mg or 150mg;2.ERS pretreatment induced ischemic tolerance;3.ERS pretreatment has a protective effect of I/R hippocampal neurons;4.XBP-1-GRp78 pathway activation may be an important mechanism for protective effects of precondition.