不同程度慢性间歇低氧诱发大鼠高血压发病过程中血管内皮功能改变的作用

目的 通过观察不同程度慢性间歇低氧(chronic intermittent hypoxia,CIH)诱发大鼠高血压过程血管活性物质水平动态变化,来探讨CIH诱发高血压发生过程中血管内皮功能改变的作用及在不同程度CIH之间差异性.方法 将168只Wistar大鼠随机分为零暴露组(UD)、不同程度间歇低氧组(重度:IH1...

Role of vascular endothelial function in the pathogenesis of hypertension induced by different degrees of chronic intermittent hypoxia

Objective To observe the change of vasoactive substances during development of hypertension induced by different degrees of chronic intermittent hypoxia (CIH) in rats, evaluate its role in the pathogenesis of CIH-induced hypertension and the differences among different degrees of CIH. Methods 168 Wistar rats were randomly divided into untreated group (UD), various degrees of intermittent hypoxia group ( severe: IH1, moderate: IH2, mild: IH3 ), continuous hypoxia groups ( CH ),sham control group (SC) and were given to different conditions. Blood pressure was observed before experiment and in weeks 2, 4, 6, 8 after the experiment. In UD group 8 rats were killed before experiment, in weeks 2, 4, 6, 8 in each other groups 8 rats were randomly selected and killed, to preserve corresponding specimens and measure nitric oxide (NO), endothelial nitricoxide synthase (eNOS),endothelin-1 (ET-1). Results In week 4, artery systolic blood pressure (SBP) of IH groups increased significantly compared with those before the experiment ( P ＜0.01), in week 8 SBP increased more apparently, the level of blood pressure was positive correlated with degree of hypoxia, IH1 group were significantly higher than IH3 group ( P ＜0.05), while no significant changes were found in the SC group and CH group. In the IH groups, changes in serum ET-1/serum NO and eNOS with experimental time showed increase/decrease trend, in weeks 8 were significantly higher/lower than the SC group ( P ＜0.01) ,the CH group ( P ＜0.05 or P ＜0. 01) and the UD group ( P ＜0.01), while changes in the SC group were not significant. In the CH group, changes in serum NO, eNOS, ET-1 of rats with experiment time were not obvious. Among groups of IH, serum ET-1, NO, eNOS levels were associated with degree of hypoxia, in weeks 4 and 6, serum ET-1 of IH1 group rats was significantly higher than the other two groups ( P ＜0. 05), while in weeks 8, serum NO, eNOS of IH1 group rats was significantly lower than that IH3 group ( P ＜0.01). Serum NO and eNOS had negative correlation with blood pressure( r =-0. 519, P ＜0.01; r = -0. 548, P ＜0. 01), serum ET-1 were positively related with blood pressure ( r=0. 615, P ＜0.01). Conclusions Changes of vascular endothelial function played an important role in the pathogenesis of hypertension induced by CIH, furthermore there was an obvious degree of hypoxia dependence and regularity of time course in the pathogenesis of hypertension induced by changes of vascular endothelial function.