镁和钾在防治大鼠心肌缺血－再灌注心律失常中的相互关系

The Interrelationship of Magnesium and Potassium Ions in Preventing Myocardial Ischaemia-Reperfusion Arrhythmias

采用Ｌａｎｇｅｎｄｏｒｆｆ灌注离体大鼠心脏模型，评价镁和钾在防治再灌注心律失常（ＲＡ）中的相互关系。结果显示：再灌注后所有心脏均在１ｍｉｎ内出现ＲＡ，其发生率随灌流液中Ｍｇ（２＋）和Ｋ＋浓度的升高而降低，当Ｍｇ（２＋）分别为０．４、１．２或４．８ｍｍｏｌ／Ｌ时，其再灌注心室颤动分别为１２／１２（１００％）、４／１２（３３．３％，Ｐ＜０．０１）、２／１２（１６．７％，Ｐ＜０．０１）。再灌注后冠脉流出液中Ｋ＋和丙二醛含量较再灌注前增加的百分率均随Ｍｇ（２＋）升高而显著降低，其中Ｋ＋分别为３１％、２７％和２２％（均为Ｐ＜０．０１），丙二醛分别为４４７％、２４２％和７７％（均Ｐ为＜０．０１）。结果提示，镁通过维持细胞内Ｋ＋平衡及降低膜脂质过氧化反应，可以预防或降低ＲＡ的发生率。

The isolated Langendorff-perfused rat heart model was used to assess the interrelationship of Mg2+ and K + in preventing reperfusion arrhythmias(RA).The result showed that all forms of ventricular arrhythmias occurred within 1 min following reperfusion in all hearts studied, and the incidence of which decreased with the increasing concentration of Mg2+ and K+ .When K+ was 4.5 mmol/L and combined with increasing Mg2+(0.4,1.2,4.8 mmol/L respectively),the occurrence rate of ventricular fibrillation on reperfusion dropped coincidently,i.e,12/12(100%),4/12(33.3%),2/12(16.7%)(all P<0.01)。The percentage of the increase of K+ and MDA after reperfusion, as compared with that before reperfusion,reduced significantly,of which K+ were 31 %,27%, 22%respectively (all P<0.01) and MDA were 447%, 242%, 77%(all P<0.01). This study suggests that Mg2+ may prevent or reduce the incidence of RA by maintaining the integrity of intracellular K+ and by reducing the lipid superoxidative reaction.