Yoshitomi Osamu, Akiyama Daiji, Hara Tetsuya, Cho Sungsam, Tomiyasu Shiro, Sumikawa Koji
Department of Anesthesiology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
J Anesth. 2005;19(2):124-30. doi: 10.1007/s00540-004-0290-0.
The present study was carried out to determine the cardioprotective effects of KB-R7943 (KBR), a selective inhibitor of the reverse mode of Na+/Ca2+ exchanger (NCX), on stunned myocardium in anesthetized dogs.
The dogs were allocated to one of three groups (n = 7 for each group), and received drug vehicle (group C), low-dose KBR (5 mg x kg(-1) i.v.) (group L) or high-dose KBR (10 mg x kg(-1) i.v.) (group H) at 15 min before left anterior descending coronary artery (LAD) occlusion. Stunned myocardium was produced by 15-min occlusion of LAD and 90-min reperfusion in all dogs. Regional myocardial contractility was evaluated with segment shortening (%SS).
Recovery of %SS at 90 min after reperfusion was significantly improved in group H (70.8% +/- 3.9% of baseline), whereas the recovery was poor in groups C and L (34.3% +/- 2.8% and 36.4% +/- 5.4% of baseline, respectively). Regional myocardial blood flow showed no significant difference among groups. KBR had no effect on coronary or systemic hemodynamics.
The results show that preischemic administration of high-dose KBR markedly improves myocardial contractile dysfunction after ischemia-reperfusion in anesthetized dogs, indicating that KBR protects myocardium against the ischemia-reperfusion injury in vivo.
本研究旨在确定钠/钙交换体（NCX）反向模式的选择性抑制剂KB-R7943（KBR）对麻醉犬顿抑心肌的心脏保护作用。
将犬分为三组（每组n = 7），在左前降支冠状动脉（LAD）闭塞前15分钟，分别给予药物载体（C组）、低剂量KBR（5 mg·kg⁻¹静脉注射）（L组）或高剂量KBR（10 mg·kg⁻¹静脉注射）（H组）。所有犬均通过LAD闭塞15分钟和再灌注90分钟来制备顿抑心肌。用节段缩短率（%SS）评估局部心肌收缩力。
再灌注90分钟时，H组的%SS恢复情况显著改善（为基线的70.8%±3.9%），而C组和L组的恢复情况较差（分别为基线的34.3%±2.8%和36.4%±5.4%）。各组局部心肌血流量无显著差异。KBR对冠状动脉或全身血流动力学无影响。
结果表明，缺血前给予高剂量KBR可显著改善麻醉犬缺血再灌注后的心肌收缩功能障碍，表明KBR在体内可保护心肌免受缺血再灌注损伤。
