缺血预适应对体外循环中心肌细胞凋亡的影响

Effect of ischemic preconditioning on cardiac myocyte apoptosis during cardiopulmonary bypass

目的观察缺血预适应(IPC)对体外循环(CPB)中心肌细胞凋亡的影响。方法将18只山羊随机分为假手术(sham)组、缺血再灌注(I／R)组及IPC组。后两组山羊均阻断升主动脉(ACC)60 min,再恢复血流灌注90 min;IPC组在ACC前先行3轮IPC(ACC 5 min,恢复血流灌注5 min)。应用原位末端探针标记(TUNEL)染色法及流式细胞仪Annexin-V／碘化丙啶(PI)双染色法检测心肌细胞凋亡率和坏死率。结果恢复血流灌注90 min后TUNEL染色法检测结果:sham组未见阳性染色细胞,I／R组见较多量阳性染色细胞,IPC组阳性染色细胞数目相对较少;IPC组心肌细胞凋亡率为(0．957±0．541)％,明显低于I／R组的(2．532±0．650)％(P< 0．01)。流式细胞仪Annexin-V／PI双染色法检测结果:恢复血流灌注90 min时,sham组心肌细胞凋亡率和坏死率分别为0和(1．476±0．552)％,IPC组分别为(0．972±0．365)％和(3．312±0．513)％,I／R组分别为(3．512±0．426)％和(7．534±0．594)％;I／R组和IPC组的心肌细胞凋亡率和坏死率均显著高于sham组(P值均< 0．05),IPC组均显著低于I／R组(P值均<0．05)。结论IPC可减少再灌注性心肌细胞凋亡的发生,从而发挥良好的内源性心肌保护作用。

Objective To observe the influence of ischemic preconditioning （IPC） on cardiac myocyte apoptosis during cardiopulmonary bypass （CPB）. Methods Eighteen goats were divided randomly into three groups： sham group（n = 6）, ischemia/reperfusion group（I/R group, n = 6） and IPC group （n = 6）. Except the sham group, the goat hearts were subjected to 60 minutes of ischemia, followed by 90 minutes o[ reperfusion （RP）. In IPC group, 3 cycles of IPC [5 min of aortic cross-clamping（ACC） and 5 min of aortic unclamping] were applied before 60 rain ACC. Cardiac myocyte apoptosis ratio was determined by TUNEL and flow cytometry with Annexin-V and propidium iodide （PI） stainings respectively. Results The result determined by TUNEL was that cardiac myocyte apoptosis ratio of IPC group [（0. 957 ± 0. 541）%] was lower than that of I/R group E（2. 532 ± 0. 650） %], P 0. 013. The result determined by Annexin-V/PI stainings was that cardiac myocyte apoptosis ratio of IPC group [（0. 972±0. 365）%] was lower than that of I/R group [（3. 512 ± 0. 426）%], P 〈 0. 051, while those of I/R group and IPC group were higher than those of sham group （0, P 〈 0.05 for both）. Conclusions IPC has a beneficial effect on recovery of cardiac performance by inhibiting cardiac myocyte apoptosis in goat heart after I/R with CPB.