摘要
目的探讨含不同Ca2+浓度的StThomasⅡ停搏液对未成熟心肌的保护作用。方法采用幼兔离体心脏灌注模型,根据停搏液中不同的Ca2+浓度,将实验分为三组(1)[Ca2+]06mmol/L;(2)[Ca2+]12mmol/L;(3)[Ca2+]24mmol/L。离体灌注心脏经20℃90分钟缺血后,37℃再灌注30分钟。结果再灌注10分钟,高Ca2+组左室功能恢复亢进,左心室形成压(LVDP),±dp/dtmax恢复率分别高于低Ca2+及中Ca2+组(P<005,P<001),再灌注20分钟,该高Ca2+组左室功能恢复呈下降的趋势。30分钟再灌注末,与其他两组相比无显著差异。高Ca2+组心肌组织Ca2+ATP酶活性显著高于中Ca2+及低Ca2+组(P<001,P<0001),而心肌ATP含量却明显低于其它两组。结论低温缺血期间,高Ca2+组细胞外滞留的Ca2+在再灌注期间经Ca2+通道和Ca2+/Na+交换途径进入心肌细胞内,激活Ca2+ATP酶而加速由Ca2+所诱导的ATP耗能过程。从未成熟心肌细胞能量代谢的角度分析,高Ca2+浓度的St.ThomasⅡ停搏液对未成熟心肌不能提供满意的心肌?
Objective To determine the myocardial protective effect of St.Thomas Ⅱ cardioplegia at different calcium concentration on immature myocardium. Methods Isolated perfused neonatal rabbit hearts from three groups (the calcium concentration of St.Thomas Ⅱ cardioplegia was modified: [Ca 2+ ] 0.6 mmol/L; [Ca 2+ ]1.2 mmol/L; [Ca 2+ ]2.4 mmol/L) were subjected to 20℃ hypothermia, 90 minutes of global ischemia followed by 30 minutes reperfusion in Langendorff mode. Results Although the recovery of LVDP, ±dp/dt max at calcium content of 2.4 mmol/L after 10 minutes of reperfusion was significantly higher than that at 0 6 and 1.2 mmol/L calcium ( P <0.05, P <0.01, respectively), the declined tendency of left ventricular hemodynamics in this group was detected after 20 minutes of reperfusion. By the end of 30 minute reperfusion, the left ventricular hemodynamic recovery at 2.4 mmol/L calcium did not differ from those at 0.6 mmol/L and 1.2 mmol/L calcium. Conversely, postischemic left ventricular functions at 0.6 and 1.2 mmol/L calcium were gradually improved during the 30 minutes reperfusion. Ca 2+ ATPase activity at 2.4 mmol/L calcium showed significant increase ( P <0.01, P <0.001), whereas ATP content was lower than that of other groups. Conclusion Calciun accumulated in extracellular space during ischemia enters myocardial cell via Ca 2+ channel and Ca 2+ /Na + exchange after reperfusion, activates Ca 2+ ATPase, and finally accelerates adenosinetriphosphate (ATP) consumption induced by calcium, which would be responsible for the results of our study. We conclude that, from the point of view of myocardial cell energy metabolism, St. Thomas Ⅱ cardioplegia at high calcium concentration can not provide immature myocardium with optimal myocardial protection.
出处
《中华医学杂志》
CAS
CSCD
北大核心
1998年第5期334-336,共3页
National Medical Journal of China
基金
江苏省教委自然科学基金
关键词
晶体停搏液
钙离子
未成熟心肌
心肌保护
Heart artrest, induced Calcium Immature myocardium Myocardial protection