核转录因子kappa B在心肌早期预缺血中的调节作用

目的　研究核转录因子kappaB(NF kB)在心肌早期预缺血中的作用。方法　 2 4只新西兰白兔随机分为预缺血组、预缺血加脯氨酸二硫氨基甲酸脂 (ProDTC ,特异性NF kB抑制剂 )组和非预缺血组。阻断和开放左冠状动脉前降支各 5min,反复 5次 ,造成局部心肌预缺血。预缺血加ProDTC组 ,ProDTC(1 5mg·kg- 1 )在预缺血前静注 ,并在预缺血中持续静滴 (1 5mg·kg- 1 ·h- 1 )。用传感探头在每次缺血末测定局部心肌的缩短率和变厚率 ,并做心肌组织病理学观察。结果　预缺血组心肌缩短率和变厚率随缺血次数增加逐渐改善 ,最终分别恢复至基础值的 85%和 82 % ,心肌结构损害轻微。预缺血加ProDTC组 ,心肌缩短率和变厚率与预缺血组相比显著减少 (P <0 .0 5) ,随缺血次数增加无改善 ,心肌损害明显。结论　核转录因子kappaB在心肌早期预缺血中起调节作用。

The mediative role of nuclear factor kappa-B in early myocardial preconditioning

Objective To study the role of nuclear factor kappa-B(NF-kB) inearly myocardial preconditioning(IPC).Methods Twenty-four New Zealand rabbits were randomly allocated to one of three groups:①preconditioned group ②preconditioned plus Proline Dithitocarbamate group (ProDTC,a specific inhibitor of NF-kB activation) ③nonpreconditioned group.Preconditioning was initiated performing for 5 cycles of 5 min regional ischemia followed by 5 min of reperfusion by tightening and releasing the snare around a branch of the left coronary artery. In preconditioned plus ProDTC group, rabbits were administered a blous of ProDTC (15mg.kg-1) prior to IPC, followed by continuous infusion (15mg.kg-1.h-1) throughout IPC.Myocardial segmental shortening and wall thickening were measured with piezoelectric crystals at the ends of ischemia.Histology was evaluated.Results Preconditioned group showed recovering segmental shortening and wall thickening with increased ischemia times,which finally reached to 85% and 82% of baseline respectively. Myocardial structure were lightly damaged. In preconditioned plus ProDTC group,segmental shortening and wall thickening decreased significantly compared to preconditioned group (P＜0.05),which showed no enhencement with increased ischemia times. Myocardial histology results indicated that there was obvious damage.Conclusion Early myocardial preconditioning is mediated by nuclear factor of kappa-B.