心跳骤停及复苏过程中脑损伤的程度及其机制

Degree and mechanism of brain injury during cardiac arrest and resuscitation

目的探讨大鼠心跳骤停及复苏过程中脑损伤的程度及机制。方法选用雄性Sprague Dawley（SD）大鼠16只，随机分为假手术组（Sham）和心跳骤停心肺复苏组（CA/CPR）。采用窒息法建立大鼠心跳骤停模型。双抗体夹心酶联免疫吸附法（ELISA）检测血清中神经元烯醇化酶（NSE）、S100β蛋白水平；Western blot检测海马凋亡蛋白B细胞淋巴瘤/白血病-2相关X蛋白（bax）、B细胞淋巴瘤/白血病-2（bcl-2）、半胱氨酰天冬氨酸特异性蛋白酶（Caspase）-3表达；原位末端转移酶标记法（TUNEL）检测神经凋亡细胞并观察大鼠脑形态学改变。结果与Sham组比较，CA/CPR组S100β在复苏后0、3、6 h含量均较高，分别为（4.488±0.762）、（6.003±0.718）、（5.913±1.817） ng/ml，且差异有统计学意义（P=0.010、0.000、0.038）；NSE在复苏后6 h含量为（15.628±3.750） ng/ml，也高于对照组的（9.376±2.865） ng/ml，差异有统计学意义（P=0.038）。CA/CPR组NSE、S100β蛋白水平呈上升趋势，S100β升高0、3 h差异有统计学意义（P=0.031、0.012）。与Sham组bax（0.326±0.041），Caspase-3（0.394±0.038），bcl-2（0.212±0.039）比较，CA/CPR组bax（0.731±0.018）、Caspase-3（0.445±0.028）表达升高，而bcl-2（0.125±0.036）表达降低，且差异均有统计学意义（P=0.000、0.001、0.003）。脑组织形态以CA/CPR组改变更明显。CA/CPR组神经元凋亡率为（29.72±6.29）%，较Sham组高，差异有统计学意义（P=0.000）。结论心跳骤停5 min及复苏成功的大鼠脑损伤比较明显，且随时间逐渐加重，可能与触发凋亡机制有关。

ObjectiveTo investigate the degree and the mechanism of brain damage induced by cardiac arrest and resuscitation in rats.MethodsA total of 16 male Sprague Dawley rats were randomly divided into the sham group and cardiac arrest/cardiopulmonary resuscitation （CA/CPR） group. The model of cardiac arrest induced by asphyxia was established and CPR was performed. Serum protein neuron specific enolase （NSE） and S100β was detected by enzyme linked immunosorbent assay （ELISA）. The levels of B cell lymphoma/leukemia-2 associated X protein （bax）, B cell lymphoma/leukemia-2 （bcl-2）, Caspase-3 protein were measured by Western boltting. Neuronal apoptosis was examined by TdT-mediated dUTP nick end labeling （TUNEL） method and morphological changes of rat brain were observed.ResultsS100β levels in CA/CPR group were （4.488±0.762）, （6.003±0.718） and （5.913±1.817） ng/ml at 0, 3, 6 h after resuscitation respectively, statistically higher than in sham group （P=0.010, 0.000, 0.038）. The levels of NSE were （15.628±3.750） ng/ml in CA/CPR group and （9.376±2.865） ng/ml in the sham group at 6 h after resuscitation, with the difference being statistically significant （P=0.038）. Serum proteins NSE and S100β were on a rise, and there was significant difference in the S100β protein levels at 0, 3 h was statistically significant （P=0.031, 0.012）. As compared with sham group [for bax, （0.326±0.041）; for Caspase-3, （0.394±0.038）; for bcl-2, （0.212±0.039）], the bax [（0.731±0.018）], and Caspase-3 （0.445±0.028） protein levels were increased, and bcl-2 [（0.125±0.036）] levels were reduced in CA/CPR group with the difference being statistically significant （P=0.000, 0.001, 0.003）. The changes in brain tissue morphology were more obvious in CA/CPR group than in sham group. The apoptosis rate of neurons in CA/CPR group was （29.72±6.29）%, higher than that in sham group （P=0.000）.ConclusionFive minutes of cardiac arrest in rats causes significant damage to brain tissue, and the damager gradually aggravates over time, whith may be related to the triggering of apoptosis.