亚低温治疗及选择时机对窒息大鼠心肺复苏后的脑保护作用

【目的】探讨亚低温治疗及选择时机对窒息大鼠心肺复苏后的脑保护作用。【方法】36只成年 SD 大鼠随机分为假手术组(6只,A 组)、常温组(6只,B 组)和亚低温治疗组(24只,C 组),C 组随机分为 C1、C2、C3和 C4组四个亚组,每组6只。A 组仅进行麻醉、气管切开及血管穿刺操作,不进行心肺复苏；B 组不行低温治疗；C1~4组分别于心脏骤停后2、4、6、8 min 立即实施心肺复苏。统计各组复苏成功率；免疫组化法检测皮质及海马组织 Nrf2及 HO-1蛋白表达；按 Elliott 法计算脑组织百分水含量。【结果】C 组皮质、海马组织 Nrf2及 HO-1蛋白表达水平均显著高于 A 组和 B 组(P <0.05)；C1、C2、C3和 C4四个亚组比较差异无统计学意义(P >0.05)。B 组和 C 组脑组织含水量均显著高于 A 组(P <0.05),但 B 组和 C 组比较差异无统计学意义(P >0.05),C1、C2、C3和 C4四个亚组比较差异也无统计学意义(P >0.05)。【结论】亚低温干预对心肺复苏大鼠的脑保护作用可能是通过激活 Nrf2-ARE 信号通路,上调 Nrf2及其下游基因 HO-1表达实现的,对窒息性心脏骤停心肺复苏后应早期进行亚低温治疗以减轻脑损伤,提高心肺复苏的成功率。

Cerebral Protection Effect of Mild Hypothcrmia at Different Time for Rats after Cardiopulmonary Resusci-tation in Anoxia

Objective]To investigate the cerebral protection effect of mild hypothermia and timing choice for rats af-ter cardiopulmonary resuscitation in anoxia.[Methods]Thirty-six cases of SD mice were randomly divided into sham-oper-ated group (A Group,n =6),normothermia group (B Group ,n=6)and mild hypothcrmia treatment group (C Group, n =24).C group was randomly divided into four subgroups of C1 ,C2 ,C3 and C4 groups,with 6 in each group.Rats in A Group just received anesthesia,tracheotomy,vascular access,without cardiopulmonary resuscitation in anoxia;rats in B Group were not treated with mild hypothcrmia;rats in C group were treated with cardiopulmonary resuscitation in an-oxia at 2,4,6 and 8 min.immediately after heart arrest,respectively.The resuscitation successful rate of each group were recorded.Immunohistochemical method were used to determine the expression of Nrf2 and HO-1 protein at cortex and hippocampus.Water content in brain tissue was calculated with Elliott method.[Results]The expression of Nrf2 and HO-1 protein at cortex and hippocampus of C Group was significantly higher than that of the other two groups (P <0.05).No significant difference was found among C1 ,C2 ,C3 and C4 Group (P >0.05).Water content in brain tissue of B Group and C Group was significantly higher than that of A Group (P <0.05),but there was no significant difference be-tween B group and C group (P >0.05),and there was no significant difference in the four subgroups of C1 ,C2 ,C3 and C4 (P >0.05).[Conclusion]The cerebral protection effect of mild hypothcrmia for rats after cardiopulmonary resuscita-tion in anoxia may be realized through Nrf2-ARE signaling pathway,by up-regulating the expression level of Nrf2 and HO-1.Mild hypothermia treatment should be carried out in the early stage of cardiac arrest after cardiac resuscitation in order to relieve the brain injury and improve the success rate of cardiopulmonary resuscitation.