摘要
目的观察重度烧伤对心肌细胞线粒体呼吸链的影响,探讨烧伤后心肌收缩功能下降及心输出量减少的机理。方法采用30%Ⅲ度烫伤大鼠模型,用差速离心法分离心肌细胞线粒体,以氧电极技术和差光谱法测定琥珀酸呼吸链和还原型辅酶 I(NADH)呼吸链的电子传递活性,同时监测心肌力学的变化。结果烫伤后2 h NADH-细胞色素 C 还原酶及细胞色素氧化酶即低于对照组,烫伤后4h 琥珀酸-Co.Q 还原酶、NADH-Co.Q 还原酶、琥珀酸-Cyt.C 还原酶也明显低于对照组。同时伴心肌收缩功能的下降。但随烫伤时间的延长(烫伤后6 h)呼吸链电子传递活性及心肌力学的变化无继续降低。结论重度烧伤后心肌细胞线粒体呼吸链电子传递活性受到全面损伤,致使心肌氧利用发生障碍,可能是心肌收缩功能下降、心输出量减少的原因之一。
Objective The electron transport chain alterations of myocardial mitochondria and car- diac dysfunction were studied after severe burn injury.Methods Contraction properties of male Sprague- Dawley rat cardiac muscle were investigated at 2,4,6 hours after 30% TBSA full-thickness thermal in- jury.Meanwhile,changes in electron transport chains of myocardial mitochondria were measured.Mito- chondria were obtained by differential centrifugation.Succinate-respiratory chains and NADH-respiratory chains were assayed polarographically and spectrophotometrically in isolated myocardial mitochondria re- spectively.Results The results showed that thermal injury led to decrease in the activities of two respira- tory chains.At 2h postburn,the activities of NADH-cytochrome C reductase and cytochrome oxidase de- clined significantly as compared with that of the sham-operated group,and at 4h postburn,all activities of succinate-Co.Q reductase,succinate-cytochrome C reductase,NADH-CO.Q reductase were much lower than those of the sham-operated group.Along with the electron transport chain alterations of myocardial mitochondria,there were decrease in myocardial contractile function in burned rats.Conclusion These re- sults imply that weakness of myocardial contractile function resulting in the decrease in cardiac output may be associated with the impairment of utilization of oxygen in myocardial mitochondria following burn in- jury.
关键词
线粒体
烫伤
呼吸链
心肌收缩性
Mitochondria
Burns
Respiratory chain
Myocardial contractile function
