| Objective: The aim was to study the effect of artificial hibernation therapy onacute myocardial infarction in rabbits and to investigate the main mechanism.Methods: A total of 28 rabbits were were divided four groups randomly:sham-operation group(A, n=6), artificial hibernation therapy and sham-operationgroup(B, n=6), acute myocardial infarction group(C, n=8), artificial hibernation therapyand acute myocardial infarction group (D, n=8). The model of acute myocardialinfarction was established in rabbits with ligation of the left anterior descendingcoronary artery. The temperature, heart rate, respiratory rate, frequency of restlessnesswas recorded. The myocardial infarct size was calculated. The level of NE in plasma,and the level of CK-MB, K+ and Mg2+ in serum were determined, then the tendencyof variation and the significance were analyzed.Results: (1) The temperature of rabbits in group C and D dropped after 1 hourof experiment(P＜0.01). That of the group C was significantly lower than the groupD(3.27℃VS 1.08℃, P＜0.01). The heart rate and respiratory rate did not changeobviously in two groups. (2) Compared with the group C, the variety degree ofCK-MB and the myocardial infarct size of the group D were more significant(473.93U/L VS 681.41U/L, 16.26% VS 19.28%, P＜0.01). (3) The level of NE inplasma and frequency of restlessness of the group D were lower than that of the groupC(44.63ng/ml VS 61.98ng/ml, 5.63 VS 7.75 , P＜0.05). (4) the level of CK-MB,K+ and Mg2+ in serum of the group C dropped slightly(P＜0.05), and that of thegroup D did not change (P＞0.05). The difference of two group was of statisticalsignificance(P＜0.05).Conclusion: (1) The results suggest artificial hibernation therapy can effectivelyrelieve the damage of cardiac muscle because of ischemia and hypoxia, and limit themyocardial infarct size. (2) The acute myocardial infarction will cause electrolytedisturbance such as the drop of K+ and Mg2+ in serum, but artificial hibernationtherapy can cancel this influence. (3) As one kind of strong stressor, the acutemyocardial infarction will cause the restlessness of rabbits and the release of NE inplasma. Artificial hibernation therapy can relieve the effect of the acute myocardial infarction on rabbits, reduce the release of NE due to acute myocardial infarction, andthen interrupt some serious complication induced by NE such as the increase ofmyocardial oxygen consumption, derangement of the body's internal environment,disorders of energy metabolism in cardiac muscle cell, the remodling of cardiacmuscle, hematic component, hemodynamic change and so on. It maybe the main themechanism through which artificial hibernation therapy produced the protecetiveeffect on cardiac muscle. (4) Artificial hibernation therapy can cause the slight drop ofthe temperature in rabbits, but it did not effect the heart rate and respiratory rate. Sowe inform that artificial hibernation therapy relieve the damage of cardiac muscleand limit the myocardial infarct size through the drop of the temperature, and have nocorrelation with the heart rate. The results also suggest that the moderate artificialhibernation therapy will not cause obvious respiratory depression. |
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