α-甲基去甲肾上腺素减轻心室颤动—复苏模型家兔心肌损伤的机制研究

Study on mechanism of alleviating myocardial injury of rabbit model of ventricular fibrillation-resuscitation by α-methylnorepinephrine

目的观察α-甲基去甲肾上腺素对心肺复苏后早期家兔心肌功能的保护作用。方法 30只清洁级家兔随机分为对照组(A组)、常规肾上腺素组(B组)和α-甲基去甲肾上腺素组(C组),每组10只。采用体外致颤法建立家兔心肺复苏模型(B组和C组),在复苏时分别静脉给药肾上腺素(B组)和α-甲基去甲肾上腺素(C组)。对致颤前及复苏后各时间点的血流动力学和血清学指标的变化进行动态监测,透射电子显微镜(透射电镜)观察复苏后心肌组织超微结构。结果在自主循环恢复后,B组和C组动物均出现心功能不全,心功能指标均显著下降(P<0.05);C组收缩斜率(peak+dp/dt)显著高于B组(P<0.05),而与A组的差异无统计学意义(P>0.05);C组舒张斜率(peak-dp/dt)显著低于A组(P<0.05)。C组血清B型利钠肽(BNP)和肌钙蛋白Ⅰ(c TnⅠ)水平显著低于B组(P<0.05)。透射电镜观察发现:C组心肌结构与A组接近;与B组比较,C组心肌损伤程度较轻。结论α-甲基去甲肾上腺素可以改善复苏后早期家兔的血清学及血流动力学指标,减轻复苏后心肌损伤,对复苏后心脏具有一定的保护作用。

Objective To investigate the protective effect of ct-methylnorepinephrine on cardiac function of rabbits at early stage after cardiopulmonary resuscitation （CPR）. Methods A total of 30 rabbits were randomly divided into the control group （group A, n =10）, epinephrine group （groups B, n =10）, and α- methylnorepinephrine group （group C, n =10）. The rabbit model of CPR （group B and C） was established by in vitro induced ventricular fibrillation. Rabbits of group B were given epinephrine and group C were given α- methylnorepinephrine during the course of CPR, respectively. Changes of hemodynamic and serum indexes were dynamically monitored before ventricular fibrillation and at each time point after CPR. The ultrastructure of myocardial tissue was observed by transmission electron microscope after CPR. Results After spontaneous circulation was restored, rabbits of both groups B and C appeared cardiac dysfunction and indexes of cardiac function significant decreased （ P〈 0.05）. The slope of contraction velocity （ peak ＋ dp/dt） of group C was significantly higher than that of group B （P 〈 0.05）, but the difference between groups C and A was not statistically significant （P〉0.05）. The slope of vasodilation velocity （peak--dp/dr） of group C was significantly lower than that of group A （P〈0.05）. The BNP and cTn I levels of group C were significandy lower than those of group B （P〈0.05）. Observation by the transmission electron microscope showed that the myocardial structure of groups C and A was similar. Compared with group B, the myocardial injury of group C was mild. Conclusion The α-methylnorepinephrine can improve hemodynamic and serum indexes, alleviate myocardial injury, and protect the cardiac function at early stage after CPR.