窒息性心搏骤停复苏对大鼠皮质黑色素瘤缺乏因子2表达的影响

The effects of asphyxial cardiac arrest/resuscitation on the absent in melanoma 2 expression in cortex of rats

目的:探讨窒息性心搏骤停/心肺复苏(CA/CPR)后的不同时间点,大鼠皮质神经元中黑色素瘤缺乏因子2(AIM2)炎症小体的表达变化以及对神经元死亡的影响。方法:健康雄性SD大鼠60只,随机分为假手术组(sham)和心肺复苏组(CPR)。CPR组实施心搏骤停/心肺复苏(CA/CPR),即5min窒息法建立心搏骤停模型后行CPR,根据复苏后时间点的不同分为五组,即1.5、3、6、12、24 h组。采用Western Blot检测皮质AIM2、凋亡相关斑点样蛋白(ASC)、含半胱氨酸的天冬氨酸蛋白水解酶-1(caspase-1)、白细胞介素-1β(IL-1β)、IL-18表达情况,免疫荧光法观察AIM2和caspase-1分别在神经元中表达情况,尼氏染色观察大鼠皮质神经元的形态变化。结果:与sham组相比,CPR组各时间点大鼠皮质AIM2、ASC、caspase-1、IL-1β、IL-18表达均增多,在12 h达到高峰(P<0.05)。免疫荧光结果显示,CPR组各时间点大鼠皮质神经元上均有AIM2、caspase-1阳性表达,其中12 h表达最多(P<0.05)。尼氏染色结果显示,CPR组各时间点皮质神经元受损严重且存活数量明显减少(P<0.01),其中12 h较6 h神经元受损数量增加(P<0.05)。结论:CA/CPR后大鼠皮质AIM2及相关炎性因子表达上调并造成神经元损伤,该作用可能是缺血性脑损伤的主要机制之一。

Objective:To investigate the expression of the absent in melanoma 2(AIM2)inflammasome and the neuronal cell death in the cortex at specific time points after cardiac arrest/cardiopulmonary resuscitation(CA/CPR).Methods:Sixty healthy male SD rats were randomly divided into the sham group and CPR group.The CPR group was performed CA/CPR,which underwent a 5-min asphyxia-based CA and CPR.The CPR group was divided into five time points after resuscitation:1.5,3,6,12,24 h.Western Blot was used to detect the expressions of AIM2,apoptosis-associated speck-like protein containing a CARD(ASC),cysteinyl aspartate specific proteinase-1(caspase-1),interleukin-1 beta(IL-1β)and IL-18.Immunofluorescence staining was used to investigate the expressions of AIM2 and caspase-1 in neurons.Morphological changes of cortical neurons were observed by Nissl staining.Results:Compared with the sham group,the expressions of AIM2,ASC,caspase-1,IL-1β,and IL-18 were gradually increased in CPR group at specific time points and peaked at 12 h time point(P<0.05).Immunofluorescence staining results showed that the number of AIM2-positive neurons and caspase1-positive neurons in CPR group was significantly increased as compared to that in the sham group,especially at 12 h time point(P<0.05).The number of viable neurons in CPR group was significantly reduced as compared to the sham group(P<0.01).Moreover,the number of viable neurons in CPR group at 12 h time point was lower than that at 6 h time point(P<0.05).Conclusion:Upregulation of AIM2 inflammasome and inflammatory factors synchronizes with the neuronal cell death in the cortex after CA/CPR,which may be one of the main mechanisms of ischemic brain injury.