[Effect of stress on myocardial apoptosis in ischemic preconditioning in rabbit hearts].

ABSTRACT

OBJECTIVE: To determine the influence of stress on myocardial apoptosis in ischemic preconditioning group (IPC). METHODS: Twenty-four Japanese white rabbits were randomly divided into 4 groups (n=6) an etomidate group (the Etom group) of depressed stress established by intravenous etomidate, an IPC group, an ischemic reperfusion group (the IR group) and a methylprednisolone group (the MP group). Myocardial apoptosis was examined by DNA-laddering, in situ nick-end labeling (TUNEL) and Hoechst dyeing. RESULTS: The DNA ladder increased in the Etom group. The percentage of apoptosis by TUNEL method was 1.7%±0.2% in the IPC group, 2.3%±0.8% in the MP group, 3.8%±1.3% in the IR group and 3.0%±0.4% in the Etom group. Hoechst dying was 4.1%±0.9% in the IPC group, 3.5%±0.4% in the MP group, 6.2%±1.6% in the IR group and 7.6%±0.4% in the Etom group. There was significant difference between the IPC group and the Etom group or IR group, and also between the MP group and the IR group. CONCLUSION: A depressed stress response impairs the inhibition on myocardial apoptosis in ischemic preconditioning. Methylprednisolone may inhibit myocardial apoptosis.