血红素氧化酶-1在离体大鼠心肌缺血预处理中的作用

目的：观察缺血预处理对离体大鼠心肌缺血再灌注后心功能、乳酸脱氢酶（LDH）活性和丙二醛（MDA）含量及血红素氧化酶-1活性的影响。方法：应用Langendorff离体大鼠等容收缩灌流模型行离体大鼠心脏灌流。缺血预处理方案为停灌5 min后再灌5 min反复3次，持续缺血再灌方案为停灌40 min后再灌20 min，监测正常对照组、缺血再灌组（IR）和缺血预处理组（IPC）心功能指标的同时，测定冠脉流出液LDH活性、心肌MDA含量和HO-1活性变化。结果：IPC组再灌20 min时的心功能恢复率显著高于IR组（P<0.01），心肌血红素氧化酶-1活性也明显高于IR组（P<0.05），而LDH活性及MDA含量显著少于IR组（均为P<0.01）。结论：血红素氧化酶-1活性增高可能与缺血预处理对大鼠缺血再灌心肌的保护作用有关。

Role of heme oxygenase-1 in the ischemic preconditioning of isolated rat heart

AIM: To investigate the influence of ischemic preconditioning on heart function, the activities of lactate dehydrogenase(LDH), malondialdehyde(MDA), and heme oxygenase-1(HO-1) after ischemia/reperfusion in isolated rat heart. METHODS: The model of Langendorff was used in isolated rat heart perfusion. Ischemic preconditioning protocol: stopping perfusion for 5 minutes and reperfusion for 5 minutes, repeating three times. Ischemia protocol: stopping perfusion for 40 minutes and reperfusion for 20 minutes. Indexes of heart function were recorded in control group, ischemia and reperfusion group(IR), and ischemic preconditioning group(IPC). The content of LDH of coronary effluent was measured. Moreover, the content of MDA and activity of HO-1 in myocardium were also measured. RESULTS: The recovery percentage of heart function in IPC group was significantly higher than that in IR group(P<0.01) and the activity of heme oxygenase-1 also increased significantly(P<0.05). CONCLUSION: The contents of LDH and MDA significantly decreased in IPC group compared with IR group. The increase in heme oxygenase-1 activity might be involved in the protective effect of ischemic preconditioning on ischemic/reperfused rat heart.