不同间歇低氧频率对大鼠血压以及血管内皮功能的影响

Effects of different intermittent hypoxia frequency on blood pressure and vascular endothelial function in rats

目的观察不同频率间歇低氧对大鼠血压的影响及其血管内皮功能的变化。方法将40只Wistar雄性大鼠随机分为常氧对照组(NC组)及4个间歇低氧组(IH1,IH2,IH3,IH4),其低氧频率分别为10次/h、20次/h、30次/h、40次/h。测定实验前后大鼠动脉收缩压、血清内皮素-1、一氧化氮水平。结果 (1)各组大鼠实验前SBP比较差异无统计学意义。6周实验结束后,各IH组SBP较实验前和NC组均显著升高(P<0.05或P<0.01);随着间歇低氧频率的增加,各IH组大鼠血压逐渐升高,但IH4组较IH3组比较差异无统计学意义。NC组SBP较实验前差异无统计学意义。(2)各IH组血清ET-1水平较NC组相比明显增高(P<0.05),血清NO水平显著降低(P均<0.01)。随着间歇低氧频率的增加,血清ET-1水平升高,NO水平显著降低(P<0.05或P<0.01)。IH4组与IH3组相比,各指标差异无统计学意义。结论血管内皮功能障碍在慢性间歇低氧致高血压过程中起着重要的作用。随着间歇低氧频率增高,血压升高及内皮损伤加重,但并非频率越高,损伤越重。

Objective To observe the effect of intermittent hypoxia with different frequencies on blood pressure and the changes of vascular endothelial function in rats. Methods 40 Wistar male rats were randomly divided into normoxic control group（NC group） and 4 intermittent hypoxia group（IH1, IH2, IH3, IH4）. The frequency of hypoxia was 10 times/h,20 times/h, 30 times/h, and 40 times/h. The arterial systolic blood pressure, serum endothelin-1 and nitric oxide levels were measured before and after the experiment. Results（1）There were no statistically significant differences in SBP between the two groups before the experiment. After 6 weeks of experiment, SBP in each IH group was significantly higher than that before experiment and that in NC group（P0.05 or P0.01）; with the increase of intermittent hypoxia frequency, the blood pressure of each IH group of rats was increased gradually, but there was no statistically significant difference between IH4 group and IH3 group. SBP in NC group was not statistically significant compared with that before experiment.（2） Compared with NC group, the levels of serum ET-1 in each IH group were significantly higher（P0.05）. Serum NO level was significantly decreased（all P0.01）. With the increase of intermittent hypoxia frequency,serum ET-1 level was increased, and NO level was significantly decreased（P0.05 or P0.01）. There was no statistically significant difference in each index between IH4 group and IH3 group. Conclusion Vascular endothelial dysfunction plays an important role in the process of hypertension caused by chronic intermittent hypoxia. With the increase of intermittent hypoxia frequency, the blood pressure is increased and the endothelial injury becomes severe. But it is not the case that the higher the frequency, the more severe the injury