Studies on the endothelial mechanism of simulated weightlessness on the reactivity of pulmonary artery / 解放军医学杂志

ABSTRACT

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 -5 mmol/L) were markedly diminished after 14 days tail-suspension, while the dilatory responses to acetylcholine (Ach, 10 -8 ~10 -6 mmol/L) were markedly enhanced. The vascular reactivity of endothelium-removed pulmonary artery rings to PE and sodium nitroprusside (SNP) did not change after 14 days tail-suspension. 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.