右美托咪定对脑缺血再灌注损伤相关炎症因子表达的影响

Effect of Dexmedetomidine on the Expression of Inflammatory Cytokines in Cerebral Ischemia-reperfusion Injury

为了探究右美托咪定对脑缺血再灌注损伤相关炎症因子表达的影响,了解其可能的发生机制。本研究将SPF级雄性SD大鼠随机分为3组(每组10只,备用3只):假手术组(Sham组)、缺血再灌注对照组(IR组)和右美托咪定治疗组(Dex组),各组大鼠适应性喂养5 d。除假手术组外各组大鼠采用线栓法制造大脑中动脉阻塞(MCAO)模型,缺血2h再灌注6h。Dex组在恢复脑部血流的同时输注浓度1.0μg/kg的右美托咪定,输注时间为1 h。每组随机挑选4只大鼠的脑组织进行氯化三苯基四氮唑(TTC)染色,计算大脑的梗死体积。高效液相色谱法检测脑组织中谷氨酸(Glu)、γ氨基丁酸(GABA)、丙二醛(MDA)含量。ELISA检测TNF-α、NF-κB、IL-1、IL-1β、IL-6和IL-18浓度。免疫蛋白印迹(Western blotting)检测Caspasel、Caspase3、Bcl-2、Bax、NLPR3和HMGB1。结果表明,IR组的脑梗死体积显著大于Sham组(p<0.05),Dex组脑梗死体积明显小于IR组,但大于Sham组(p<0.05)。IR组和Dex组Glu、MDA含量显著高于Sham组(p<0.01),Dex组低于IR组(p<0.05),而GABA含量则是先下降后上升,即Sham组>Dex组>IR组(p<0.05)。IR组和Dex组TNF-α、NF-κB、IL-1、IL-1β、IL-6和IL-18的表达水平均极显著高于Sham组、Dex组,除了IL-18、TNF-α、NF-KB、IL-1β、IL-6和IL-1的表达水平均低于Sham组(p<0.05)。Western blotting结果表明:IR组Caspase1、Caspase3、Bcl-2、Bax、NLPR3和HMGB1的表达水平均高于Sham组(p<0.05),而Dex组Caspase3和HMGB1的表达水平均低于IR组(p<0.05);IR组Caspase1、NLPR3、Bcl-2和Bax的表达水平虽低于Dex组但没有统计学差异。缺血再灌注损伤会引发炎症级联反应,引起细胞凋亡和细胞焦亡,造成大面积脑梗死,而DEX能抑制一些炎症因子表达,保护脑组织,DEX是否具有保护脑组织细胞凋亡、焦亡和自噬这方面的功能还需要进一步研究。

To investigate the effect of dexmedetomidine on the expression of inflammatory cytokines in cerebral ischemia-reperfusion injury and to understang its possible mechanism.SPF male Sprague-Dawley rats were randomly divided into 3 groups(10 in each group and 3 in reserve):Sham operation group(Sham group),ischemiareperfusion control group(IR group) and dexmedetomidine treatment group.(Dex group),each group of rats was adaptively fed for 5 days.Rats in the middle cerebral artery occlusion(MCAO) model were treated with suture method except the sham operation group.The rats were reperfused for 6 hours after ischemia for 2 hours.The Dex group was infused with dexmedetomidine at a concentration of 1.0 μg/kg while restoring blood flow to the brain for an infusion time of 1 h.B rain tissue of 4 rats randomly selected from each group was stained with triphenyl tetrazolium chloride(TTC) to calculate the infarct volume of the brain.The content of glutamic acid(Glu),gamma aminobutyric acid(GABA) and malondialdehyde(MDA) in brain tissue was determined by high performance liquid chromatography.The concentrations of TNF-α,NF-κB,IL-1,IL-1β,IL-6 and IL-18 were measured by ELISA.Western blotting was used to detect Caspasel,Caspase3,Bcl-2,Bax,NLPR3 and HMGB1.The result showed that the cerebral infarction volume of the IR group was significantly larger than that of the Sham group(p<0.05).The cerebral infarction volume of the Dex group was significantly smaller than that of the IR group,but greater than that of the Sham group(p <0.05).The contents of Glu and MDA in the IR group and the Dex group were significantly higher than those in the Sham group(p <0.01),and the Dex group was lower than the IR group(p<0.05).The GABA content decreased first and then increased.That is,Sham group>Dex group>IR group(p<0.05).The expression levels of TNF-α,NF-κB,IL-1,IL-1β,IL-6 and IL-18 in IR group and Dex group were significantly higher than those in Sham group,except for IL-18.The expression levels of TNF-α,NF-κB,IL-1β,IL-6 and IL-1 were lower than those in Sham group(p<0.05).Western Blot results showed that the expression levels of Caspasel,Caspase3,Bcl-2,Bax,NLPR3 and HMGB1 in IR group were higher than those in Sham group(p <0.05),while the expression levels of Caspase3 and HMGB1 in Dex group were lower than IR.The expression levels of Caspasel,NLPR3,Bcl-2 and Bax in the IR group were lower than those in the Dex group,but there was no statistical difference.Ischemia-reperfusion injury can trigger the inflammatory cascade;causing apoptosis and cell death and causing large-area cerebral infarction.DEX can inhibit the expression of some inflammatory factors and protect brain tissue.Does DEX have protective brain cells?The functions of apoptosis,coercion and autophagy need further research.