不同复苏措施对猪心肺复苏后心肌凋亡的影响

Effects of different resuscitation modalities on post-resuscitation myocardial apoptosis in porcinemodels of cardiac arrest

目的本研究探讨猪心肺复苏后的心肌功能障碍是否有凋亡机制的参与以及心肺复苏的策略选择对于凋亡是否有影响。方法22头五指山小型猪被随机（随机数字法）分为假手术组（SHAM）（6只）、先除颤组（DF）和先按压组（CF）（各8只）。建立室颤8min小型猪模型，监测各组的血流动力学指标，用Westernblot法检测心肌组织Bcl-2、Bax和caspase一3的蛋白表达，用实时荧光PCR法定量caspase一3的mRNA水平，TUNEL法检测心肌组织凋亡。应用SPSS17．0统计软件进行数据处理，组间比较采用成组t检验，多组均数比较用方差分析。以P〈0．05为差异具有统计学意义。结果室颤8min，CF、DF组小型猪心肌功能发生严重障碍。恢复自主循环24h后，CF、DF组心肌细胞的Bcl．2、Bax和caspase-3蛋白表达较SHAM组均明显升高（P〈0．05），但是Bcl-2／Bax却在下降。CF、DF组心肌细胞凋亡指数明显高于SHAM组（P〈0．05）。在恢复自主循环6h后，虽然DF组比CF组的血流动力学指标显著改善，但DF组与cF组在Bcl-2、Bax和caspase-3的蛋白表达及凋亡指数之间，差异无统计学意义（P〉0．05）。结论凋亡机制可能参与了心肺复苏后猪心肌功能障碍，但心肺复苏的策略选择对于凋亡的影响并不大。

Objective To confirm whether in post-resuscitation myocardial dysfunction involved in myocyte apoptosis mechanism in porcine model of cardiac arrest and apoptosis index varied from different modalities of cardiopulmonary resuscitation or not. Methods A total of 22 WZSP inbred small swine were randomly （random number） divided into sham operation group （SHAM） （n =6）, defibrillation first group （ DF, n = 8） and chest compression first group （ CF, n = 8 ）. Eight minutes after ventricular fibrillation was set up, standard CPR was carried out subsequently after defibrillation in porcine models of cardiac arrest in DF group and defibrillation after standard CPR in CF group, and hemodynamics were monitored. Twenty- four hours after restoration of spontaneous circulation （ ROSC ） , animals were sacrificed, and myocardial specimens were examined with electron microscopy, Western blot, quantitative RT-PCR, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL） assay. The experimental data were analyzed by SPSS 17.0. Student＇ s t test was employed for comparisons between two groups, Differences within groups at different time intervals were compared with repeated measures ANOVA. A two-tailed value of P 〈 0. 05 was considered statistically significant. Results Myocardial function was significantly impairedafter ROSC. Levels of Bcl-2, Bax and caspase-3 protein was markedly increased in the CF and DF groups than those in the SHAM group （P 〈 0. 05） at 24 h after ROSC, while Bcl-2/Bax was significantly reduced in the CF and DF group compared with the SHAM group （ P 〈 0. 05 ）, and much more apoptotic cells were observed in cardiac arrest animals in comparison with sham-operation animals （ P 〈 O. 05 ）. Six hours after ROSC, hemodynamic indicators improved significantly in group DF than those in group CF, but Bcl-2, Bax and caspase-3 protein levels and apoptotic index were not significantly different bewteen the DF group and CF group （P 〉 0. 05 ）. Conclusions Caspase-3-mediated apoptosis might be one of the main pathological mechanisms of postresuscitation myocardial injury in a porcine model of cardiac arrest, but there was no statistically significant difference in apoptosis index between two resuscitation modalities, showing no one modality was superior over another.