Intracellular calcium dynamics in mouse model of myocardial stunning
Intracellular calcium dynamics in mouse model of myocardial stunning
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DOI：
10.1152/ajpheart.1998.274.5.h1821
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发表时间：
1998-05-01
影响因子：
4.8
通讯作者：
Morgan, JP
中科院分区：
文献类型：
--
作者：
Hampton, TG;Amende, I;Morgan, JP
本实验采用小鼠冠状动脉灌流心脏，测定心肌细胞内钙（Ca ~（2+））浓度和左室功能，探讨Ca ~（2+）在心肌缺血再灌注损伤中的作用机制。提供了在恒定流条件下将发光蛋白水母发光蛋白加载到等容收缩小鼠心脏中的具体方法。该方法允许在心肌顿抑模型中逐搏检测Ca 2+的变化，并允许调节Ca 2+交换的干预与功能改变的相关性。对23只冠状动脉灌注的小鼠心脏进行15分钟的缺血，随后进行20分钟的再灌注。在13个心脏中，灌注液包括钙调素拮抗剂W7（10 μ M），以抑制Ca 2 +-钙调素调节机制。在对照组中峰值Ca-1（2+）为0.77 +/-0.03 μ M，并且在基线时不受W7的影响。缺血的特征在于LV功能的快速下降，随后是缺血性挛缩，伴随着Ca-i（2+）的逐渐上升。再灌注的特征在于Ca-i（2+）的初始爆发和逐渐恢复到接近正常的收缩期Ca-i（2+），而LV压力在再灌注20分钟后恢复到55%（顿抑心肌）。小鼠心脏中的这些结果证实，顿抑不是由Ca 1（2+）缺乏引起的，而是由肌丝自身的变化引起的肌丝对Ca 1（2+）的反应性降低引起的。在用W7灌注的心脏中，缺血期间Ca-i（2+）的升高显著减弱，早期再流期间平均Ca-i（2+）的幅度也是如此。缺血性挛缩消失或延迟。用W7灌注的心脏显示出显著改善的LV压力恢复、收缩率和舒张率。在对照心脏中，在顿抑期间舒张Ca-i（2+）增加，但在用W7灌注的心脏中恢复至基线。钙离子和左心室功能的同时评估表明，钙调素调节机制可能有助于小鼠心脏心肌顿抑的发病机制。
Intracellular calcium (Ca-i(2+)) and left ventricular (LV) function were determined in the coronary-perfused mouse heart to study Ca-i(2+)-related mechanisms of injury from myocardial ischemia and reperfusion. Specifics for loading of the photoprotein aequorin into isovolumically contracting mouse hearts under constant-flow conditions are provided. The method allows detection of changes in Ca-i(2+) on a beat-to-beat basis in a model of myocardial stunning and permits correlation of interventions that regulate Ca2+ exchange with functional alterations. Twenty-three coronary-perfused mouse hearts were subjected to 15 min of ischemia followed by 20 min of reperfusion. In 13 hearts, the perfusate included the calmodulin antagonist W7 (10 mu M) to inhibit Ca2+-calmodulin-regulated mechanisms. Peak Ca-i(2+) was 0.77 +/- 0.03 mu M in the control group and was unaffected by W7 at baseline. Ischemia was characterized by a rapid decline in LV function, followed by ischemic contracture, accompanied by a gradual rise in Ca-i(2+) Reperfusion was characterized by an initial burst of Ca-i(2+) and a gradual recovery to nearly normal systolic Ca-i(2+) while LV pressure recovered to 55% after 20 min of reperfusion (stunned myocardium). These results in the mouse heart confirm that stunning does not result from deficiency of Ca-i(2+) but rather from a decreased myofilament responsiveness to Ca-i(2+) due to changes in the myofilaments themselves. In hearts perfused with W7, the rise in Ca-i(2+) during ischemia was significantly attenuated, as was the magnitude of mean Ca-i(2+) during early reflow. Ischemic contracture was abolished or delayed. Hearts perfused with W7 showed significantly improved recovery of LV pressure, rate of contraction, and rate of relaxation. Diastolic Ca-i(2+) was increased in control hearts during stunning but returned to baseline in hearts perfused with W7. Simultaneous assessment of Ca-i(2+) and LV function demonstrates that calmodulin-regulated mechanisms may contribute to the pathogenesis of myocardial stunning in the mouse heart.