尾部悬吊对大鼠基底动脉收缩与舒张反应性的影响

Effects of tail-suspension on vascular contractile and relaxation responsiveness in basilar arteries from rats

目的 尾部悬吊可导致大鼠基底动脉血管收缩反应性增强 ,本实验拟探讨尾部悬吊大鼠基底动脉血管环反应性变化机制中是否存在血管内皮功能的改变 .方法 2 0只大鼠被随机分为模拟失重组 (SUS)与同步对照组 (CON) ,每组各1 0只 .采用尾部悬吊大鼠模型模拟失重影响 .利用离体基底动脉血管环测定其对 KCl的收缩反应性和乙酰胆碱 (Ach)及硝普钠 (SNP)的舒张反应性 .结果 悬吊组大鼠基底动脉血管环对 KCl的最大反应 (7.1 5± 0 .53) m N较对照组 (5.37±0 .2 7) m N显著升高 (P<0 .0 5) ;而对 Ach或 SNP的舒张反应性在悬吊组 [Ach:(45.46± 3.61 ) % ;SNP:(96.58±4.37) % ]和对照组 [Ach:(47.75± 5.78) % ;SNP:(92 .65±5.62 ) % ]之间无显著差异 .结论 尾部悬吊可导致大鼠基底动脉血管环收缩反应性显著升高 。

AIM It is known that the vascular contractile responsiveness in basilar arteries from tail suspended rats was enhanced, the purpose of the work is to investigate whether there are alterations of vascular endothelium function in mechanism of changes in responsiveness of basilar arteries from tail suspended rats. METHODS A total of 20 rats were divided into simulated microgravity group and synchronous control group. Simulated microgravity rats were subjected to tail suspension for 4 wk to simulate the effect of weightlessness, responses of perfused isolated basilar arterial rings to KCl, acetylcholine (Ach), and sodium nitroprusside (SNP) were examined. RESULTS Maximal isometric contractile responses to KCl were significantly enhanced in arterial rings isolated from 4 wk tail suspension rats (7.15± 0.53 ) mN as compared with that from simultaneous control rats (5.37±0.27) mN ( P <0.05). However, dilatory responses to Ach and SNP in arterial rings isolated from 4 wk tail suspended rats [Ach: (45.46±3.61)%; SNP: (96.58±4.37)%] were no different as compared with that from simultaneous control rats [Ach: (47.75±5.78)%; SNP: ( 92.65 ±5.62)%]. CONCLUSION These results indicate that 4 wk tail suspension may result in an enhanced contractile responsiveness in rat basilar artery, but has no significant effects on dilatory responsiveness in rat basilar artery.