磷酸肌酸后处理对大鼠脑缺血-再灌注损伤的影响

摘要

目的：观察磷酸肌酸(phosphocreatine,PCr)后处理对大鼠脑缺血-再灌注损伤的影响。方法36只雄性 SD 大鼠随机均分为三组：假手术组(Sham 组)、缺血-再灌注组(IR 组)和磷酸肌酸后处理组(PCr 组)。采用线栓法建立大脑中动脉缺血-再灌注模型,PCr 组和 IR 组于再灌注即刻分别静脉注射 PCr 180 mg/kg 和等量生理盐水。再灌注24后行头颅核磁共振和神经体征缺失评分；观察脑组织病理改变,测定脑组织梗死体积及血浆丙二醛(MDA)、4-羟基壬烯醛(4-HNE)浓度；采用免疫组织化学法检测皮质神经元特异性核蛋白(NeuN)以及促凋亡基因 caspase-3的表达水平；免疫荧光双染色4,6-二脒基-2-苯基吲哚(DAPI)及碘化丙啶(PI),NeuN 及 caspase-3测定神经元凋亡指数。结果与 IR 组比较,PCr 组大鼠神经体征缺失评分、脑梗死体积及血浆 MDA 和4-HNE 均明显降低(P <0.05)；皮质 NeuN 表达明显增加,caspase-3表达明显降低,神经元凋亡指数明显下降(P <0.05)。结论磷酸肌酸后处理可缩小脑缺血-再灌注梗死体积,改善神经功能,其机制可能与抑制氧化应激及 caspase-3途径细胞凋亡有关。%Objective To investigate the effects of phosphocreatine postconditioning on cerebral ischemia-reperfusion(IR)injury in rats.Methods Thirty-six SD rats were randomly divided into three groups:groups Sham,IR (treated with normal saline)and PCr.IR was induced by intraluminal middle cerebral artery occlusion (MCAO).All treatments were given intravenously at the begining of reperfusion.Twenty-four hours after the reperfusion, neurological deficit score and magnetic resonance scan were performed.serum concentrations of malonaldehyde and 4-hydroxynonenal,cere-bral infarct volume and destruction of cerebral cortex were estimated.Neuronal apoptosis was further assessed by immunohistochemistry and immunofluorescent staining of caspase-3 and NeuN. Results Compared with group IR,phosphocreatine significantly decreased neurological deficit score, infarct volume,malonaldehyde and 4-hydroxynonenal levels(P < 0.05 ).Cortex structure was more complete,as well as neuronal apoptotic index was smaller in group PCr (P <0.05).Conclusion PCr can reduce cerebral infarct volume,thereby promote neurofunctional recovery.The mechanism of Pcr is related to reduced oxidative stress and inhibitted apopotosis during IR.