亚低温治疗对心肺复苏后Wistar大鼠心肌氧化应激损伤的影响

Effect of mild hypothermia on the oxidative stress induced myocardial injury after cardiopulmonary resuscitation

目的 建立Wistar大鼠心跳骤停（CA）-心肺复苏模型，观察心肺复苏后亚低温治疗对心肌线粒体氧化应激损伤及心功能的影响。方法 18只雄性Wistar大鼠建立室颤-心肺复苏（VF-CPR）模型，自主循环恢复（ROSC）后随机分为常温治疗组和亚低温治疗组（即NORM组与Hypothermia组）。用超声评估两组动物1~4小时的心脏射血分数（EF）、缩短分数（FS）和心输出量（SV）等心脏功能变化；检测心肌细胞内谷胱甘肽（GSH）、丙二醛（MDA） 与三磷酸腺苷（ATP）含量；以及透射电镜下心肌线粒体超显微结构的变化。结果ROSC后两组动物基础生命支持（BLS）的时间、肾上腺素用量以及除颤次数均无明显统计学差异（P〉0.05）； Hypothermia组较NORM组心肌细胞内GSH、MDA及ATP含量均有显著差异（P〈0.05）；心脏超声评估显示，ROSC后亚低温治疗能够显著提高EF、FS和SV；透射电镜下观察显示，Hypothermia组心肌线粒体损伤的程度较NORM组明显减轻（线粒体损伤评分：0.21±0.04VS 0.42±0.08，P〈0.05）。 结论 亚低温能够减轻Wistar大鼠心肌氧化应激损伤，改善ROSC后心脏收缩功能和舒张功能。

Objective To observe the effects of mild hypothermia on the myocardial mitochondrial injury induced by oxidative stress after restoration of spontaneous circulation （ROSC） in rat of cardiac arrest model. Methods Eighteen male Wistar rats were randomly （raudom number） divided into normal temperature group and mild hypothermia group after ROSC. Ultrasound was used to measure the left ventricular ejection fraction （ EF）, shortening fraction （FS） and stroke volume （SV）. The levels of glutathione （GSH）, malondialdehyde （MDA） and adenosine triphosphate （ATP） in myocardium were detected. The ultramicroscopic structure of myocardial mitochondria was observed under transmission electron microscope at 4 h after ROSC. Results There were no significant differences in basic life support （BLS） time, dosage of epinephrine and number of defibrillation attempt between two groups （P 〉 0. 05 ）. The concentrations of GSH and ATP in myocardium of rats in hypothermia group were significantly higher than those in normal temperature group, while the level of MDA was significantly lower in hypothermia group than that in normal temperature group. Echocardiographic findings showed that hypothermia could significantly improve the EF, FS and SV after ROSC. The hypothermia decreased the myocardial mitochondria injury rather than normothermia [mitochondrial injury score： （0. 21±0. 04） vs. （ 0. 42±0.08）, P 〈 0. 05 ]. Conclusions In this model, mild hypothermia can decrease myocardial oxidative stress injury, improving the cardiac function after ROSC.