二氮嗪对移植鼠心不同时期心肌组织ATP酶活性的作用

目的探讨二氮嗪对移植鼠心在术后不同时期心肌细胞膜Na^＋-K^＋-ATPase和肌浆网Ca^2＋-ATPase活性的变化及其对心肌缺血再灌注损伤的作用。方法采用改良Heron法大鼠颈部异位心脏移植模型。sD雄性大鼠随机分为实验组、对照组和拮抗组，并在术后不同时间（5min、1周、3个月）留取标本，检测心肌细胞膜Na^＋-K^＋-ATPase和肌浆网Ca^2＋-ATPase活性，及观察心肌超微结构。结果（1）实验Ⅰ、Ⅱ组心肌细胞膜Na^＋-K^＋-ATPase和肌浆网Ca^2＋-ATPase活性均显著高于相应对照Ⅰ、Ⅱ组（P〈0．05）；实验组中Ⅰ、Ⅱ、Ⅲ组心肌细胞膜Na^＋-K^＋-ATPase活性增高呈递减性显著性减弱（P〈0．05），实验Ⅰ组肌浆网Ca^2＋-ATPase活性显著高于实验Ⅱ、Ⅲ组；余差异无显著性。（2）拮抗组取消实验组DE的这一增高作用。（3）中长期各组均有良好的心肌超微结构保护，肌节清，线粒体肿胀不明显，嵴结构尚清楚，排列整齐；仅Ⅲ组偶有空泡变性。结论二氮嗪对移植鼠心长期冷缺血保存后，有更好的保存和提高细胞膜Na^＋-K^＋-ATPase和肌浆网Ca^2＋-ATPase的活性，减轻心肌缺血再灌注损伤，维持心肌能量代谢有效地进行来发挥心肌保护作用。

Study on the influences of diazoxide on Na+- K+- ATPase of rat's myocardium at different stage following heart transplantation

Objective To evaluate influences of diazoxide on sarcolemmal Na^＋- K^＋ - ATPase and sareoplasmic reticulum（SR）Ca^2＋ - ATPase activity in diffe,,ent time following heart transplantation of rats and its effects in ischemic reperfusion injury. Methods One hundred and twelve rats were randomly divided into control group, experiment group and resistant group. The modified Heron＇ s technique for heterotopic cervical cardiotransplantation in rats by cuff vessel anastomosis was used. The donor＇ s rat hearts were stored in 4℃ Celsior cardioplegia solution or Celsior solution containing diazoxide （30mol/L） with or without blocker 5 - hydroxydecanoate （5 - HD, 100 mol/L） for 5 hours. And the myocardia which samplinged in 5min, 1 week, 3month time after heart transplantation were used to measure the activities of sarcolemmal Na^＋ - K^＋ - ATPase and SRCa^2＋ - ATPase. The myocardial ultrastructure was also determined. Results （1）Diazoxide improved the activities of sarcolemmal Na^＋ - K^＋ - ATPase and SRCa^2＋ - ATPase in the excperiment group Ⅰ and Ⅱ than the control group Ⅰ and Ⅱ . In the experiment group, the sarcolemmal Na^＋ - K^＋ - ATPase were significantly degressively ordinal reduced within group Ⅰ , Ⅱ and Ⅲ . The SRCa^2＋ - ATPase in the gronp Ⅰ were significantly excelled to group Ⅱ and Ⅲ; and other were not. （2）The cardiac effects of diazoxide were attenuated by 5 - HD. （3）Myocardial uhrastructure injury was alleviated. Conclusions The results suggest that diazoxide could improve the activities of sarcolemmal Na^＋ - K^＋ - ATPase and SRCa2 ＋ - ATPase in the cardioplegia and repeffusion period, and decrease the myocardiac damages of ischemia- repeffusion, that enhance myocardial protection.