后处理减轻心肌缺血/再灌注损伤与HIF-1α-iNOS-cGMP通路激活的关系

The relationship between the cardioprotection of postconditioning against ischemia/reperfusion injury and the activation of HIF-1a-iNOS-cGMP pathway

目的 探讨后处理减轻缺血/再灌注所致的心肌损伤效应是否与低氧诱导因子-1α （HIF-1α）及其下游通路有关.方法 建立大鼠心肌缺血/再灌注及后处理模型,检测心肌组织中HIF-1α及其下游基因诱导性一氧化氮合酶（iNOS）的表达情况及cGMP的含量.结果 后处理缩小缺血/再灌注所致的心梗面积[（27.30±4.16）%比 （36.00±5.29）%,P＜0.01],减少心肌细胞凋亡（Caspase 3比活性：（1.85±0.50）比（3.79±0.64）,P＜0.01）,上调心肌组织中HIF-1α表达[（5.76±0.55） 比（2.85±0.13）,P＜0.01）的同时,提高了iNOS的表达及其cGMP的含量.预先给予HIF-1α脯氨酸羟化酶抑制剂DMOG使后处理心肌组织中HIF-1α表达进一步上调后,iNOS的表达及cGMP含量随之增加,同时后处理减轻心肌损伤的效应[心梗面积：（17.95±2.00）% 比 （27.30±4.16）%,P＜0.01; Caspase3比活性：0.43±0.13比1.85±0.50,P＜0.01]也进一步增强.结论 后处理减轻缺血/再灌注所致心肌损伤的效应可能与其激活心肌组织中HIF-1α-iNOS-cGMP通路有关.

Objective To explore whether the cardioprotection of postconditioning against ischemia/reperfu- sion injury is related to the activation of the HIF-1a-iNOS-eGMP pathway. Methods Adult male Wistar rats underwent the left anterior descending coronary artery 30 min myocardial ischemia （I） and 180 rain reperfusion （R） with or without postconditioning （PostC, i.e., 3 cycles of 10 s R/I after onset of the reperfusion）. Myocardial damage was evaluated by infarct size and Caspase 3 activity. The expressions of HIF-1a and iNOS were examined by Western blot and real time-PCR. The content of cGMP was detected by the method of radioimmunology. Results Postconditioning attenuated myocardial infarct size [ （27.30±4.16）% vs （ 36.00±5.29 ）%, P〈0.01 ] and the activity of Caspase 3 （1.85±0.50 vs 3.79±0.64, P〈0.01 ）, and simultaneously increased the expression of HIF-1a （5.76± 0.55 vs 2.85±0.13, P〈0.01） compared with I/R group. Meanwhile, the expression of iNOS and the content of cGMP were also increased by postconditioning. After upregulation of HIF-1a-iNOS-cGMP by DMOG, the cardioprotective effects of postconditioning were further enhanced, including the decrease of infarct size [ （17.95±2.0）% vs（27.3±4.16）%, P〈0.01 ] and activity of Caspase 3 （0.43±0.13 vs 1.85±0.50, P〈0.01 ）. Conclusion The cardioprotection of postconditioning may be related to the activation of the pathway of HIF-1a-iNOS-cGMP.