大鼠心肌缺血预适应中cAMP含量变化观察

目的 :研究心肌缺血预适应时 ,腺苷酸环化酶 (AC)及cAMP变化及意义。方法 :选择SD大鼠 ,随机分成预适应组 (IP组 ) ,缺血 /再灌注组 (I/R组 )及假手术组 (CON组 ) ,手术套管法造成左冠脉主干缺血及再灌注。损伤后取心脏用TTC法测梗塞面积 ,取血清测心肌酶改变 ,测AC活性变化 ,放免测cAMP水平。结果 :IP组较I/R组心梗面积明显缩小 (p <0 0 0 1) ,心肌酶CK、CK—MB、LDH明显降低 (p <0 0 0 1)。IP组较I/R组AC活性增高 (p<0 0 5 ) ,cAMP含量增加 (p<0 0 0 1)。结论 :心肌缺血预适应保护心脏 ,缩小梗塞面积 ,减少心肌酶漏出 ,cAMP可能在预适应保护作用中起重要作用。

The Effect of Myocardial Ischemic Preconditioning on cAMP Content in Rat Myocardium

Objective To study effects of ischemic preconditioning of myocardium on adenyl cyclase and cAMP content in rat myocardial in vivo. Methods SD rats were randomly divided into three groups: IP group (n=12), I/R group (n=12) and CON group (n=6). Surgical procedure included intermittent left coronary artary occluision and reperfusion for 5 minates each for two times followed by 30 minutes occlusion and 90 minutes reperfusion (IP group) and simply 30 minutes occlusion plus 90 minutes reperfusion (I/R group). After sacrifice of the experimental animals, the hearts were taken out to assessment of the infarction size with TTC staining and myocardial AC activity and cAMP contents were measured with RIA. Serum myocardial enzymes were also measured to both groups. Results Infarct areas were much smaller in IP group than those in I/R group ( p <0 001). CK, CK-MB, LDH were significantly higher in I/R group ( p <0 001). In IP group, the activity of AC and the content of cAMP were much higher than those in I/R group ( p <0 05 and 0 001, respectively). Conclusion Ischemic preconditioning could afford some protaction to heart to reduce the area of necrosis and endo-enzyme leakage, through the incrose of myocardial AC activity and cAMP content