大鼠在模拟5000米低氧下心力储备的动态变化

THE DYNAMIC CHANGES OF THE CARDIAC RESERVE IN RATS AT SIMULATED HIGH ALTITUDE HYPOXIA OF 5000 M

目的和方法 :采用电刺激大鼠坐骨神经引起心阻抗图相应参数变化来测算心力储备的方法 ,测定了大鼠在模拟 5 0 0 0m低氧下不同时间心力储备的动态变化。结果 :心力储备在低氧 3d己开始增加 ,7d增加显著 (P <0 .0 5 ) ,低氧 10d及 14d又降至接近正常组水平 ,低氧 30d略低于正常水平 ;每搏储备的变化规律和变化量均与心力储备相近 ,低氧 7d增加显著 (P <0 .0 1) ,低氧 14d仍显著高于对照组 (P <0 .0 5 ) ;心率储备变化不大。结论 :与心室压及其变化率等指标相比 。

Aim and Methods: We estalished a method to measure the cardiac reserve of rat by electrically stimulating the sciatic nerve of the animals and then calculating the relevant parameters in impedance cardiogram. The dynamic changes of the cardiac reserve of rats were measured after the animals were exposed to the simulated high altitude hypoxia of 5000 m for different duration. Results:The cardiac reserve increased after 3 days hypoxia, and increased significantly (P<0.05) after 7 days hypoxia. The cardiac reserve decreased to almost the control level after 10 days or 14 days hypoxia, and decreased slightly below the control level after 30 days hypo xia . The changes of the characteristic and quantity in the stroke reserve were similar to that in the cardiac reserve, and the stroke reserve increased significantly (P<0.01) after 7 days hypoxia and still remained significantly (P<0.05) after 14 days bypoxia. There were no obvious changes in the reserve of heart rate. Conclusion: Comparing with the other hemodynamic parameters such as ventricle pressures and their change rates, the cardiac reserve seemed more efficiently to reflex the changes of cardiac function during the hypoxic acclimatization.