ABSTRACT
Objective: To explore myocardial protection effect of artificial subhibernation therapy on rabbits with acute myocardial infarction (AMI) and its possible mechanism. Methods: A total of 24 rabbits were randomly and equally divided into sham operation group, AMI control group and AMI subhibernation group. Changes of their body temperature, heart rate and respiratory frequency were observed. Serum concentration of creatine kinase isoenzyme (CK-MB) was measured by immunosuppression method, and plasma concentration of norepinephrine (NE) was measured by high performance liquid chromatography-electrochemical method. Percentage of myocardial infarct area in left ventricular area (I/LV) and apoptosis index (AI) were compared between two AMI groups. Results: Compared with control group 4 h after establishment of AMI model, there were significant decrease in body temperature [(37.333±0.427)℃ vs. (34.988±0.488)℃], I/LV [(19.281±1.687)% vs. (16.263±2.275)%] and AI [(36.636±1.671)% vs. (34.521±1.356)%], and concentration of CK-MB [(759.863±64.111)U/L vs. (560.225±65.837)U/L] and NE [(200.475±43.581) ng/ml vs. (143.813±43.383) ng/ml] in subhibernation group, P<0.05,or <0.01, but there were no significant changes in heart rate and respiratory frequency between two groups. Conclusion: Artificial subhibernation therapy possesses significant myocardial protection effect on rabbits with acute myocardial infarction through reducing stress response, inducing low temperature and inhibiting cell apoptosis etc.