缺血后适应对活性氧及心肌细胞凋亡的影响

Influence of postconditioning on reactive oxygen and cardiomyocyte apoptosis

目的观察后适应和远程后适应对大鼠缺血再灌注模型活性氧生成及心肌细胞凋亡的影响,探讨活性氧在后适应和远程后适应中的作用。方法大鼠随机分为6组:①假手术组:只穿线,不结扎;②模型组:前降支缺血30min后再灌注2h;③后适应组:前降支缺血30min后进行3个循环后适应(缺血10s,再灌注10s,然后再灌注2h;④远程后适应组:前降支缺血24min时结扎右股动脉5min,在再灌注前1min开通股动脉,前降支再灌注2h;⑤2-巯基丙酰基甘氨酸组1;⑥2-巯基丙酰基甘氨酸组2:在缺血20min时尾静脉注射2-巯基丙酰基甘氨酸20mg/kg,余处理分别同组③和(或)④。实验结束后检测血丙二醛,心肌标本行HE染色、TUNEL检测和测定Bcl-2、BaxmRNA。结果①血丙二醛活性:后适应组、远程后适应组、2-巯基丙酰基甘氨酸组1和组2分别为(14.6±1.4)、(15.6±1.5)、(14.4±1.6)、(15.0±1.4)’mol/L,低于模型组(18.3±1.9)’mol/L,(P<0.05);②后适应组和远程后适应组Bcl-2表达高于模型组,而Bax表达低于模型组(P<0.05);2-巯基丙酰基甘氨酸处理有对抗作用;④细胞凋亡率:后适应组(25.3±2.3)%和远程后适应组(26.7±2.2)%低于模型组(50.0±7.9)%(P<0.05),2-巯基丙酰基甘氨酸处理有对抗作用。结论后适应和远程后适应均能减少活性氧的产生;后适应和远程后适应都有减少细胞凋亡作用,其心肌保护作用与减少活性氧的产生有关;提示活性氧可能在后适应和远程后适应中发挥重要作用。

Objectives To investigate the influence of ischemic postconditioning and remote ischemic postconditionging on apoptosis and to test the hypothesis that reactive oxygen species （ROS） is involved in the cardiac protective effect of ischemia postconditioning （IPC） and remote ischemia postconditioning （RIPC）. Methods Rats were randomly divided into 6 groups： sham operation group （SHAM） ; control group （CON） ： 30 min coronary artery occlusion followed by 2 h of reperfusion; IPC group： 30 min coronary artery occlusion followed by 2 h of reperfusion with three cycles of 20 s coronary artery reperfusion/ischemia; RIPC group： 30 rain coronary artery occlusion followed by 2 h of reperfusion with femoral artery ischemia/reperfusion before coronary artery reperfusion; MPG＋IPC group： 2-mercaptopropionyglycine （MPG）, a ROS scavenger, was administered 10 rain before IPC and MPG＋RIPC group： MPG was administered 10 min before RIPC. Results MDA in IPC, RIPC, MPG＋IPC and MPG＋RIPC groups were （14.6±1.4） , （15.6±1.5） , （14.4±1.6） , （15.0±1.4） μmol/L, repectively, which were lower than that in the CON group （18.3±1.9） μmol/L; IPC and RIPC had increased Bcl-2 expression and at the same time reduced Bax expression compared to the CON group, There was no significant difference in Bcl-2 and Bax expression among CON, MPG＋IPC and MPG＋RIPC groups. IPC and RIPC reduced apoptosis （25.3±2.3）%, （26.7±2.2） %, P〈0.05, respectively, as compared to the CON group （50±8）%. These cardiac protective effects were abolished by MPG administered before IPC or RIPC [ （44±6） %, （45±7） %, respectively]. Conclusions Both IPC and RIPC reduce the production of ROS; Both IPC and R｜PC show cardiac protective effect to reduce apoptosis and the cardiac protective effect was associated with the reduction of ROS; ROS may act as trigger signal and play an important role in IPC and RIPC.