模拟失重时肺动脉反应性变化的内皮机制研究

Studies on the endothelial mechanism of simulated weightlessness on the reactivity of pulmonary artery

目的研究血管内皮在模拟失重时肺动脉反应性变化中的作用。方法32只雄性Wistar大鼠随机分为尾悬吊组和对照组,采用尾悬吊模拟失重大鼠模型模拟微重力效应,制备离体肺动脉环测定其对几种血管活性物质的反应性变化,经去内皮处理后再测定其对血管活性物质的反应性变化,并进行分析比较。结果与对照组相比,14天尾悬吊模拟失重大鼠肺动脉环对KCl(68mmol/L)和苯肾上腺素(10-7～10-5mmol/L)的收缩反应性明显下降,对乙酰胆碱(10-8～10-6mmol/L)的舒张反应性明显增强。而去内皮处理后,肺动脉环对苯肾上腺素的收缩反应性恢复,对硝普钠的舒张反应性无明显变化。结论模拟失重引起肺动脉血管内皮结构或功能改变,是导致其血管发生反应性变化的重要原因。

Ojective To study the endothelial mechanism of simulated weightlessness on the reactivity of pulmonary artery. Methods Experiments were conducted using 32 Wistar male rats, which were randomly divided into 2 groups： tail-suspended group and control group, 16 rats for each group. Tail-suspension for 14 days was used to simulate the effects of microgravity. The changes in responses of pulmonary artery to several vascular active agents were determined by using in vitro vessel rings perfusion technique. And the changes were determined again after the endothelium of pulmonary artery was removed. Results Compared with the control group, the contractile responses of pulmonary artery to potassium chloride （68mmol/L） and phenylephrine （PE, 10^-7 ×10^-5mmol/L） were markedly diminished after 14 days tail-suspension, while the dilatory responses to acetylcholine （Ach, 10^-5× 10^-6 retool/L） were markedly enhanced. The vascular reactivity of endotheliurn-removed pulmonary artery rings to PE and sodium nitroprusside （SNP） did not change after 14 days tailsuspension. Conclusion The contractile responsiveness is attenuated and the dilatory responsiveness is enhanced in the rats＇ pulmonary arteries after simulated weightlessness. That the pulmonary artery endothelium changes in structure or function after simulated weightlessness might be an important cause of changing in the reactivity of pulmonary artery.