心肺复苏中大鼠心肌细胞膜β_1-肾上腺素能受体与心肌损伤研究

Mechanism of myocardial injury and β_1-adrenergic receptor during cardiopulmonary resuscitation in rats

目的:探讨在心肺复苏中肾上腺素对自主循环恢复前大鼠心肌损伤与心肌细胞膜β1-肾上腺素能受体的关系。方法:健康雄性(SD)大鼠50只随机分为4组:空白对照组10只(O组)、复苏对照组10只(C组)、大剂量肾上腺素组15只(H组)、标准剂量肾上腺素组15只(S组)。制备大鼠心肺复苏模型,窒息致心跳停止,再进行心肺复苏,心跳恢复立即取心肌标本,检测各组心肌组织Na+-K+-ATP酶和超氧化物歧化酶活力、环磷腺苷和丙二醛浓度并进行统计分析;电镜观察心肌细胞超微结构变化。结果:S组与H组心肌ATP酶和超氧化物歧化酶活力、丙二醛浓度比较差异有统计学意义(P<0.05或P<0.01);心肌环磷腺苷含量S组、H组比较差异无统计学意义(P>0.05),且与心肌损伤程度无相关性;电镜观察各组心肌细胞超微结构变化差异均有统计学意义(P<0.05)。结论:心肺复苏中肾上腺素在自主循环恢复前已加重了心肌组织的损伤,而心肌细胞膜β1-肾上腺素能受体兴奋性增高可能不是主要的原因。

Objective To investigate the relationship of epinephrine with myocardial injury and β1-adrenergic receptor before restoration of spontaneous circulation during cardiopulmonary resuscitation. Methods Fifty SD male rats were randomly divided into 4 groups： blank group （group O, n=10）, resuscitation control group （group C, n=10）, standard-dose epinephrine group （group S, n=15） and high-dose epinephrine group （group H, n=15）. The cardiopulmonary resuscitation＇ models of rat was established. As soon as the heartbeat was resuscitated, the Na^＋ -K^＋ -ATPase and SOD activities and concentrations of MDA and cAMP in cardiac muscle were detected and analyzed. The ultramicrostructure of cardiac muscle cell was observed on electron microscope. Results ATPase, activity of SOD and concentration of MDA in group S were significantly different from those in group H （P〈0. 05,P〈0.01）. There was no significant difference in cAMP concentration between group S and group H（P〉0.05）, which was not correlated to the degree of myocardial injury. There was a significant difference in ultramicrostructure of cardiac muscle cell on electron microscope between every two groups. Conclusion During cardiopulmonary resuscitation, epinephrine has increased myocardial injury before restoration of spontaneous circulation, but myocardial injury might not he caused by increased excitability of β1-adrenergic receptor.