缺血预处理对缺血再灌注心肌细胞凋亡的影响

Effect of ischemic preconditioning on apoptosis of myocardial cells during cardiac ischemia/reperfusion

目的 :观察缺血预处理 (ischemicpreconditioning ,IPC)对体外循环中缺血再灌注心肌细胞凋亡的影响 ,评价其对心肌的保护作用。 方法 :在猫体外循环 (cardiopulmonarybypass,CPB)模型的基础上随机分成 3组 :组 1(单纯CPB组 ,n =18)和组 2 (主动脉阻断组 ,n =18)于CPB开始 4 5min后阻断主动脉 ,6 0min后开放主动脉使心脏恢复再灌注 90min ;组 3(IPC组 ,n =18)于主动脉阻断前进行IPC(阻断升主动脉 5min后开放 10min ,并重复 3次 ) ,余处理与组 2相同。应用Annexin Ⅴ /PI联合染色、流式细胞仪检测心肌细胞膜磷脂酰丝氨酸的外翻 ,比较IPC处理组及单纯缺血再灌注组体外循环过程中 4 5、10 5、195min时间点心肌细胞坏死和凋亡的数量。 结果 :组 2于主动脉阻断 6 0min及再灌注 90min时心肌细胞坏死率分别为(2 .6 75± 0 .4 2 4 ) %及 (5 .32 7± 0 .5 13) % ,而组 3则分别为 (1.317± 0 .2 92 ) %和 (3.112± 0 .32 8) % ,两组主动脉阻断 6 0min时 ,均未检出凋亡心肌细胞 ,但在再灌注 90min时 ,组 2和组 3的心肌细胞凋亡率分别达 (2 .32 7± 0 .6 73) %和 (0 .94 3± 0 .14 6 ) %(P <0 .0 1)。IPC处理组缺血再灌注期间坏死及凋亡的心肌细胞明显减少。 结论 :IPC不仅能减少体外循环缺血再灌注导致的心肌细胞坏?

Objective:To elucidate the effect of ischemic preconditioning(IPC) on apoptosis of myocardial cells under ischemia/reperfusion during cardiopulmonary bypass (CPB).Methods:Fifty four felines were randomized into 3 groups:Group 1 ( n =18),CPB was conducted without aortic cross clamping (ACC); Group 2 ( n =18),with 60 min ACC followed by 90 min reperfusion,and cardioplegia was used during period of ACC; Group 3 ( n =18),with protocol similar to that of group 2 except for three round 15 min IPC applied before ACC.Apoptosis of myocytes was detected 45,105 and 195 min after CPB in all groups by flow cytometry with Annexin Ⅴ and propidium iodiode (PI) staining.Results:In both group 2 and 3,necrosis was found during either ischemia or reperfusion periods,but myocyte apoptosis was only detected during the period of reperfusion.IPC significantly decreased the ratio of necrosis myocytes both in ischemic and reperfusion periods during CPB ,being (2.675± 0.424)% in group 2 vs (1.317±0.292)% in group 3 after 60 min ACC; (5.327±0.513)% in group 2 vs (3.112±0.328)% in group 3 after 90 min reperfusion.Moreover,IPC markedly attenuated the ratio of apoptosis of myocardial cells caused by reperfusion from (2.327±0.673)% in group 2 to (0.943±0.146)% in group 3( P <0.01).Conclusion:IPC may protect myocardial cells from ischemia and reperfusion injury by inhibiting both necrosis and apoptosis during CPB.