60天头低位卧床期间心功能的变化及振动和中药的对抗作用

目的 通过观察和比较60 d头低位（HDT）卧床期间振动和中药对心脏功能的影响，旨在进一步明确不同对抗方式对失重不良影响的对抗效果。方法 21名健康男性被试者，随机分为对照组、振动组和中药组，每组7人。对照组仅-6°HDT卧床60 d，口服安慰剂; 振动组和中药组在HDT卧床期间分别进行阻抗振动锻炼和口服太空养心丸。卧床前、卧床30、60 d测量心脏泵血、收缩功能。结果 对照组每搏量（SV）和心排出量（CO）在卧床30 d较卧床前显著降低(P<0.05)，在60 d进一步降低(P<0.05)，TPR在卧床60 d显著升高(P<0.05)；振动组SV和CO在卧床60 d较卧床前显著降低(P<0.05)，总外周阻力（TPR）显著升高(P<0.05)；中药组在卧床期间上述指标的变化均未达到显著水平。3组射血前期与左室射血时间的比值(PEP/LVET)、等容收缩时间与左室射血时间的比值(ICT/LVET)在卧床60 d较卧床前均显著增加(P<0.05)；中药组PEP/LVET和ICT/LVET在卧床60 d较对照组和振动组均显著降低(P<0.05)。结论 60 d头低位卧床可引起心脏泵血和收缩功能显著降低。在卧床期间服用中药可明显改善心脏泵血和收缩功能，而振动锻炼对心脏泵血和收缩功能有一定改善作用。

Changes of cardiac function during 60-day head-down tilt bed rest and effects of vibration exercise and Chinese medicine as countermeasures

AIM: To observe and compare the effects of vibration exercise and Chinese medicine on cardiac function during 60 d head-down tilt (HDT) bed rest. METHODS: Twenty one healthy, male subjects were randomly divided into control, vibration and Chinese medicinegroups (seven subjects in each group). All subjects were exposed to -6° HDT for 60 d. Control group received placebo, vibration group received vibration training and the Chinese medicine group received taikong yangxin pill. Cardiac systolic and pump functions were measured before HDT (supine) and on days 30 and 60 of HDT. RESULTS: In the control group, stroke volume (SV) and cardiac output (CO) decreased significantly on day 30 of HDT (P<0.05) and further decreased on day 60 of HDT (P<0.05), whereas total peripheral resistance (TPR) increased significantly on day 60 of HDT (P<0.05). In the vibration group, SV and CO decreased significantly on day 60 of HDT (P<0.05) and TPR increased significantly on day 60 of HDT (P<0.05). In the Chinese medicine group, no significant changes were observed during HDT. In all groups, pre-ejection period/left ventricular ejection time (PEP/LVET) and isovolumetric contraction time/left ventricular ejection time (ICT/LVET) increased significantly on day 60 of HDT (P<0.05). On day 60 of HDT, PEP/LVET and ICT/LVET decreased significantly in the Chinese medicine group compared with the control group and vibration group (P<0.05). CONCLUSION: HDT during a 60 d period may induce a reduction of the cardiac pump and systolic function. Chinese medicine significantly improves the cardiac pump and systolic function during bedrest, whereas the effect achieved by vibration exercise is less significant than by Chinese medicine.