间断性头高位对模拟失重兔股静脉及颈静脉内皮素表达的影响

Change of ET-1 expression in femoral vein and jugular vein in rabbits under simulated weightlessness and intermittent head-up tilt

目的观察21 d模拟失重及间断性头高位45°对兔股静脉及颈静脉内皮素(ET-1)表达的影响。方法24只健康雄性兔,随机分为对照组、模拟失重组和对抗组,每组8只。模拟失重组在21 d实验期间保持头低位-20°。对抗组在21 d模拟失重期间每天保持45°头高位倾斜2 h。实验结束后取股静脉和颈静脉,用免疫组化方法观察ET-1表达的变化。结果正常对照组股静脉组织ET-1表达明显,颈静脉组织表达不明显;21 d模拟失重后,股静脉ET-1表达水平明显降低,颈静脉ET-1明显升高;对抗组的股静脉和颈静脉ET-1表达水平与对照组比较无明显改变。结论21 d模拟失重可引起兔股静脉ET-1表达减少,颈静脉ET-1表达增高;每天2 h头高位45°可对抗模拟失重所引起的股静脉及颈静脉ET-1表达的改变。

Objective To observe the effects of simulated weightlessness and intermittent 45° head-up tilt on the change of endothelin （ET-1） expression in femoral vein and jugular vein in rabbits. Methods Twenty-four healthy male rabbits were randomly divided into three groups： control group, simulated weightlessness （SW） group and countermeasure group, 8 rabbits in each group. Rabbits of SW group were exposed to head-down tilt for 21 days. For countermeasure group, rabbits were arranged keeping in 45° head-up tilt position 2 h per day during 21 d head-down tilt. The ET-1 expression levels of femoral vein and jugular vein were studied by immunohistochemical methods after 21 d exposure. Results ET-1 expression in femoral vein from control rabbits was prominent and extensive, while in jugular vein the expression was less prominent and less extensive. The ET-1 expression level in femoral vein from rabbits of SW group was significantly decreased as compared with that of controls, while the ET-1 expression in jugular vein was significantly increased. No significant change of ET-1 expression of femoral vein and jugular vein from rabbits of countermeasure group was found. Conclusions Twenty-one days simulated weightlessness may induce lowering of ET-1 expression in femoral vein and increase of ET-1 expression in jugular vein of rabbits. Two hours 45° head-up tilt per day may counteract the changes of ET-1 expression in femoral vein and jugular vein in- duced by simulated weightlessness.