Zn^(2+)预处理对离体大鼠缺血再灌注损伤心肌的保护作用

Protective Effect of Zn~ (2+) Preconditioning on Ischemic/Reperfused Myocardium in Isolated Rat Heart

目的 :观察Zn2 + 预处理诱导金属硫蛋白 (MT)在心肌细胞的表达及对离体大鼠缺血再灌注损伤心肌的保护作用。方法 :3 2只Sprague Dawley大鼠随机分为对照组及实验组 ,实验组按腹腔注射ZnSO4 到建立再灌注模型的时间分为E1 2h,E2 4h及E4 8h组 ,每组各 8只。检测LDH ,CK、ATP含量及心功能指标 (LVSP与±dp/dtmax) ,用1 0 9Cd/血红素饱和法测量心肌组织中金属硫蛋白的含量。结果 :E2 4h及E4 8h组MT表达量较对照组高 (P <0 .0 1) ,E1 2h组虽有表达 ,但其与对照组间差异无显著性。E2 4h及E4 8h组LDH与CK较其它二组低 ,而ATP较其它二组高 ,心功能指标较其它二组改善。E1 2h组及对照组之间相应各指标 (LDH ,CK、ATP、LVSP与±dp/dtmax)间差异无显著性 (P >0 .0 5 )。结论 :Zn2 + 预处理可诱导MT在心肌细胞的表达而对离体大鼠缺血再灌注损伤心肌具有保护作用。

Objective: To observe the protective effects of Zn 2+ preconditioning by expressing metallothionein(MT) on Ischemia/reperfusion myocardium in isolated rat heart.Method: 32 Sprague-Dawley rats were randomly divided into 4 groups ( n= 8,in each group). According to the time of ZnSO_4 being injected into the belly cavity of the rats,the experimental group were divided into 3 subgroups:E_ 12h ,E_ 24h and E_ 48h group. The levels of CK,LDH and ATP which indicated myocardium injury and the cardiac function(LVSP and ±dp/dt max) were observed in this study. The expression levels of MT were estimated by the 109 Cd/hemoglobin affinity assays. Results: The expression levels of MT in E_ 24h and E_ 48h group is higher than other two groups with the difference is very significant ( p <0.01). The expression levels of MT in E_ 12h group is higher than in control group,but the difference has not significant. Compared with control group,the levels of LDH and CK in both E_ 24h and E_ 48h groups reduced,the ATP contents increased,and the cardiac function (LVSP and ±dp/dt max) is improved ( P <0.01,respectively).Conclusion: Zn 2+ preconditioning has protective effects on reperfused myocardium in isolated rat hearts by highly expressing MT.