线粒体通透性转换孔在精脒介导的心肌缺血再灌注损伤中的作用

Effect of mitochondrial PT pore on ischemia reperfusion injury of heart by spermidine

目的:研究线粒体通透性转换(PT)孔在精脒介导的心肌缺血/再灌注损伤中的作用。方法:采用Langendorff灌流离体大鼠心脏,全心停灌30min,复灌120min造成心肌缺血复灌模型。采用高效液相色谱法测定心肌组织精脒含量;复灌前10min给予不同浓度精脒,记录左室收缩压(LVSP)、左室压上升/下降最大速率(±dp/dtmax)和左室舒张末期压力(LVEDP);用紫外分光光度法检测复灌10min的冠状动脉(冠脉)流出液乳酸脱氢酶(LDH)活性;用TTC染色法测心肌梗死面积。检测不同浓度精脒对心肌线粒体PT孔开放改变(520nm吸光度变化)。结果:与对照组比较,大鼠心肌缺血期及再灌期精脒含量均减少(P<0.05);与单纯缺血/复灌组相比,于复灌前10min给予线粒体通透性转换孔特异性阻断剂环孢菌素A(CsA 0.2mol/L)和精脒(0.1mol/L、1μmol/L、5μmol/L),左室收缩舒张功能改善,其中LVSP上升(P<0.01),LVEDP下降(P<0.01),±dp/dtmax提高(P<0.01);冠脉流出液中LDH含量明显减少(P<0.01),梗死面积减少(P<0.01)。而于复灌前10min给予精脒(10μmol/L,15μmol/L),与单纯缺血/复灌组比较,LVSP均明显下降(均P<0.01),LVEDP明显上升(P<0.01),±dp/dtmax下降(P<0.01);复灌10min后冠脉流出液中LDH含量明显增加(P<0.01),梗死面积均增加(均P<0.01);在分离的线粒体给予精脒,高浓度PT孔开放幅度增加;低浓度开放受到抑制。结论:精脒可通过抑制或增强线粒体PT孔开放而对缺血/再灌心肌产生保护或加重损伤的作用。

Objective：To investigate the effect of spermidine in myocardial ischemia reperfusion injury. Method：Langendorff perfusion apparatus was used to record the contractile function and heart rate of isolated rat hearts.Spermidine content of myocardial tissue was measured by HPLC（High Performance Liquid Chromatography）.The lactate dehydrogenase（LDH） activity was measurd spectrophotometrically.Inarct size was measured by TTC method.Mitochondrial swelling method was used to measure the MPTP opening of isolated mitochondria. Result：Compared with control group,spermidine content was decreased both in ischemia and reperfusion period（P〈0.05）.During the first 10 min in CSA（0.2 μmol/L） group and groups treated with spermidine of different concentrations（0.1 μmol/L,1 μmol/L,5 μmol/L）,reperfusion was improved（P〈0.05）,LVSP was increased and LVEDP was decreased（P〈0.05）,which were associated with reduced infarct size and LDH release.However,during the first 30 min in 10 μmol/L and 15 μmol/L permidine groups,reperfusion had a decreased recovery of LVSP or improved LVEDP,which were associated with reduced infarct size and LDH release. Conclusion：Spermidine may provide either cardioprotection by inhibiting MPTP or myocardial injury by increasing MPTP open,and it is dependent on the concentration of spermidine used.