应激对心肌缺血预适应保护作用的影响

Role of stress in myocardial protection of ischemic preconditioning

目的:探讨应激反应对心肌缺血预适应保护的影响。方法:30只家兔随机分为5组:缺血预适应组(IPC组)、缺血再灌注组(IR组)、依托咪酯组(Etom组)、甲基强的松龙组(MP组)和假手术组(Sham组),以心肌梗死面积/缺血面积、血清肌酸激酶(CK)活性、肌钙蛋白I(cTnI)浓度为检测指标,同时检测血清皮质醇动态变化。结果:IPC组、MP组、IR组、Etom组心肌梗死面积/缺血面积分别为(5.86±2.81)%,(11.28±3.62)%,(26.79±4.53)%,(18.19±3.72)%,CK活性分别增加(255±89),(314±160),(855±371),(768±404)U/L,cTnI增高值分别为(3.6±0.6),(6.1±2.2),(8.1±3.6),(6.4±1.6)μg/L。各指标组间比较,差异均有统计学意义(P<0.05),Etom组皮质醇反应明显钝化。结论:钝化皮质醇反应可明显削弱IPC的保护作用,甲基强的松龙有一定程度的心肌保护作用,提示IPC保护作用中可能有应激反应参与。

Objective： To determine the role of stress in myocardial protection ofischemic preconditioning （IPC）. Methods： q-hirty rabbits were randomly divided into an IPC group, an etomidate （Etom） group, an ischemic/reperfusion （IR） group, a methylprednisolone （MP） group and a sham group. The ratio of infarction size versus risk area （infarct/risk） was calculated, q-he elevations of the serum creatine kinase （CK） activity and cardiac troponin I （cTnI） concentrations as well as the serum cortisol concentrations were measured. Results： The percentages of infarct/risk in the IPC group, the MP group, the IR group, and the Etom group were （5.86±2.81）%, （11.28±3.62）%, （26.79±4.53）%, and （18.19±3.72）%, respectively. The elevations of the serum CK activity in the IPC group, the MP group, the IR group, and the Etom group were （255±89）, （314±160）, （855±371）, and （768±404） U/L, respectively. The elevations of serum cTnI concentrations in the IPC group, the MP group, the IR group, and the Etom group were （3.6±0.6）,（6.1±2.2）, （8.1±3.6）, and （6.4±1.6）μg/L, respectively. Those indicators among the groups were significantly different （P〈0.05）. Cortisol reaction was markedly diminished in the Etom group. Conclusion： A blunted cortisol reaction can markedly reduce the benefit of IPC while methylprednisolone shows cardioprotective effects, suggesting that stress might be involved in the myocardial protection of IPC.