Role of stress in myocardial protection of ischemic preconditioning

Abstract

To determine the role of stress in myocardial protection of ischemic preconditioning (IPC). Thirty 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. The elevations of the serum creatine kinase (CK) activity and cardiac troponin I (cTnI) concentrations as well as the serum cortisol concentrations were measured. 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. 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.