镁离子对豚鼠心脏离体缺血再灌注损伤的影响

Effects of magnesium ion on myocardial ischemia/reperfusion injury in isolated guinea pig hearts

目的观察不同浓度镁离子对豚鼠离体心脏缺血再灌注损伤的影响。方法建立离体心脏缺血再灌注模型,应用含不同浓度镁离子的Krebs-henseleit(KH)液,观察心率(heartrate,HR)、冠脉流量(coronary flow,CF)以及灌流液中乳酸脱氢酶(lactate dehydrogenase,LDH)等指标的变化。结果缺血再灌注模型组与正常对照组(Control)相比较,HR、CF和CF/HR均有明显降低,而灌流液中LDH含量明显增加。与模型组相比较,低浓度镁离子再灌注诱发缺血再灌注损伤心脏的HR异常增加,对CF、CF/HR、LDH含量没有影响。高浓度镁离子再灌注对HR没有影响,却增加了CF和CF/HR,同时降低灌注液中LDH含量。结论低镁增加缺血再灌注中的心率,可能带来增加耗氧量,增大心律失常的危险性。而高镁可能通过改善心肌收缩力(CF/HR)降低缺血再灌注损伤。

Objective To investigate the effects of magnesium ions on myocardial ischemia/reperfusion injury in isolated hearts of guinea pig. Methods The isolated heart ischemia/reperfusion injury model was established. Krebs-henseleit(KH) solutions containing magnesium ions with different concentrations were used. The index of heart rate(HR) and coronary flow(CF) were observed, and lactate dehydrogenase(LDH) was measured. Results Compared with the normal control group, HR, CF and CF/HR were significantly decreased, while LDH content in the perfusion fluid was significantly increased in ischemia/reperfusion injury model. Compared with the model group, the low concentration of magnesium ions induced HR to increase abnormally, but had no effect on CF, CF/HR and LDH. However, the high concentration of magnesium ions and reperfusion did not affect the HF, but increased the CF and CF/HR. Given the high concentration of magnesium ions, CF was 1.7, 1.7, 1.4, 1.4, 1.3, 1.4 and 1.3 times of the model group at the 15, 20, 25, 30, 40, 50, 60 min during the perfusion respectively;the CF/HR raised to 2.6, 2.4, 2.1, 2.3, 1.9, 2.0 and 1.8 times. Administered the high concentration of magnesium ions, LDH were decreased to 87% and 42% of model group at the 15 and 40 min during the perfusion respectively(P<0.01). Conclusion The low concentration of magnesium ions increased the heart rate during ischemia/reperfusion injury, leading to increased oxygen consumption and increased risk of arrhythmia. However, the high concentration of magnesium ions decreased the myocardial ischemia reperfusion injury by improving the myocardial contractile force(CF/HR).