丰富环境对脑缺血再灌注损伤大鼠细胞焦亡的影响

Effects of the enriched environment on pyroptosis in rats with cerebral ischemia-reperfusion injury

目的探讨丰富环境(EE)对脑缺血再灌注损伤(CIRI)大鼠细胞焦亡的影响.方法45只雄性Sprague-Dawley大鼠随机分为3组:假手术(Sham)组、脑缺血再灌注(CIR)组和丰富环境(EE)组,各组15只大鼠.除Sham组外,其余两组均建立右侧大脑中动脉闭塞模型.术后EE组饲养于EE,其余两组饲养于标准环境.在造模前及术后第1天、第7天和第14天时对各组进行改良神经损害严重程度评分(mNSS).术后第14天时采用2,3,5-氯化三苯基四氮唑(TTC)染色评估脑梗死体积,苏木素-伊红(HE)染色观察各组缺血侧海马CA1区组织病理形态学改变,免疫组化方法检测CA1区组织核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)和含半胱氨酸的天冬氨酸蛋白水解酶-1(caspase-1)蛋白的表达,透射电镜观察CA1区神经细胞超微结构改变.结果术后第1天和第7天时,与Sham组相比,CIR组和EE组mNSS评分均升高(P<0.05),但此两组之间差异无统计学意义(P>0.05).术后第14天时,与CIR组相比,EE组mNSS评分和脑梗死体积减小(P<0.05),组织病理形态学改变减轻,NLRP3和caspase-1蛋白表达水平降低(P<0.05),神经细胞超微结构中的焦亡病理改变减轻.结论EE可减轻CIRI大鼠神经功能损害,缩小脑梗死体积,发挥脑保护作用,其作用机制可能与下调经典焦亡途径相关蛋白NLRP3和caspase-1的表达从而抑制细胞焦亡有关.

Objective To explore the effect of the enriched environment(EE)on pyroptosis in rats with cerebral ischemia-reperfusion injury(CIRI).Methods 45 male Sprague-Dawley rats were randomly divided into three groups:a sham surgery(Sham)group,a cerebral ischemia-reperfusion(CIR)group and an enriched environment(EE)group,with 15 rats in each group.Except for the Sham group,the right middle cerebral artery occlusion model was established in the other two groups.After surgery,the EE group was fed in EE,and the other two groups were fed in standard environment.All the rats were assessed using the modified neurological severity score(mNsS)before modeling and on the lst day,7th day and 14th day following surgery.On the 14th day after surgery,2,3,5-triphenyltetrazolium chloride(TTC)staining was used to evaluate the infarct volume,hematoxylin and eosin(HE)staining was used to examine pathomorphological changes of the hippocampal CA1 region on the ischemic side of the rats in each group,immunohistochemical assay was used to detect the expression of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)and cysteinyl aspartate specific proteinase-1(caspase-1)proteins in the CA1 region,and ultrastructural changes in neurons in the CAl region were observed under transmission electron microscopy.Results Compared with the Sham group,the mNSS scores of the CIR group and the EE group were significantly higher on the 1st day and 7th day after surgery(P<0.05),but there was no significant difference between the CIR and EE groups(P>0.05).On the 14th day after surgery,compared with the CIR group,the EE group showed a decrease in the mNSS score and the cerebral infarct volume(P<0.05),alleviated pathomorphological changes,decreased expression of NLRP3 and caspase-1 proteins(P<0.05),and alleviated pathological changes of pyroptosis in the ultrastructure of neurons.Conclusions EE can reduce the damage of neurological function,reduce the cerebral infarct volume,and play a protective role for the brain in CIRI rats.The mechanism may be related to the downregulation of the expression of NLRP3 and caspase-1 proteins related to the classical pyroptosis pathway,leading to the inhibition of pyroptosis.