[Regulative effects of Chinese herb-compound on blood rheology and circulatory system of rabbits under simulated weightlessness].

Objective: To investigate effects of Chinese herb-compound on blood rheology and circulatory system of rabbits under simulated weightlessness in order to provide bases for protecting against the influence of simulated weightlessness on cardiovascular function.

Method: Rabbits were exposed to head-down tilt (HDT -20 degrees) for 9 d to simulate weightlessness. The effect of Chinese herb-compound on indices related to blood rheology, blood-fat and orthostatic tolerance in these rabbits were examined.

Result: After head-down tilt, hematocrit value and red blood cells deformability decreased significantly; cholesterol and low density lipoprotein increased markedly; plasma fibrinogen content and triglyceride showed increasing trend. Administration of the Chinese herb-compound didn't improve the blood rheology indices, but showed a trend to decrease triglyceride and to inhibit the increase of cholesterol. In the head-up tilt (HUT) plus lower body negative pressure (LBNP) experiment, orthostatic tolerance time of the rabbits in the control group decreased, and myocardial ischemic changes in ECG, such as dropped ST segment, inverse T wave, and arrhythmia were observed. While in the Chinese herb-compound group, the heart rate of the rabbits kept smooth, ischemic changes in ECG were not clear, and orthostatic tolerance time increased.

Conclusion: The Chinese herb-compound shows an effect of preventing orthostatic tolerance from decreasing, and improves blood-fat metabolism. It regulates different human systems on the whole, and increases ability of adaptation to ill environment.