Rodway George W, Sethi Jigme M, Hoffman Leslie A, Conley Yvette P, Choi Augustine M K, Sereika Susan M, Zullo Thomas G, Ryter Stefan W, Sanders Mark H
University of Pittsburgh Division of Pulmonary Allergy and Critical Care Medicine, University of Pittsburgh School of Nursing [corrected] USA.
Transl Res. 2007 Feb;149(2):76-84. doi: 10.1016/j.trsl.2006.09.005.
The hemodynamic response to hypoxia may be influenced by exposure pattern and inducible biological signals, such as nitric oxide synthase (iNOS) expression. The systemic blood pressure (BP) and heart rate (HR) response to intermittent and continuous hypoxia (IH and CH) were examined as was the relationship between these responses and iNOS expression in 10 normal subjects. BP and HR were recorded during exposure to IH or CH (total hypoxic time=60 min/dayx3 days for each exposure profile), whereas arterial oxygen saturation (SpO2) was maintained at 80-90%. Total RNA was isolated from peripheral blood lymphocytes before exposure on Day 1 and 2 hours after the last exposure on Day 3, and it was assayed for iNOS messenger RNA (mRNA) expression using quantitative polymerase chain reaction (PCR). HR, systolic BP (SBP), and diastolic BP (DBP) increased during both experimental conditions (P<0.05), with no difference by exposure pattern or evidence of facilitation over 3 days. No significant change occurred in iNOS mRNA during IH or CH when pre- and post-exposure values were compared. However, iNOS expression at the end of Day 3 was negatively correlated with the average end-exposure DBP (r=-0.79) and mean BP (MBP; r=-0.76) on Days 1-3 of the IH (P<0.05), but not CH exposure. It is concluded that both IH and CH are associated with significant but comparable hemodynamic changes. The negative correlation between BP and iNOS mRNA with IH, but not CH, may suggest differential modulation of the hemodynamic response to the 2 exposure patterns.
对缺氧的血流动力学反应可能受暴露模式和可诱导生物信号（如一氧化氮合酶（iNOS）表达）的影响。在10名正常受试者中，研究了对间歇性和持续性缺氧（IH和CH）的全身血压（BP）和心率（HR）反应，以及这些反应与iNOS表达之间的关系。在暴露于IH或CH期间记录BP和HR（每种暴露模式下，总缺氧时间=60分钟/天×3天），而动脉血氧饱和度（SpO2）维持在80%-90%。在第1天暴露前和第3天最后一次暴露后2小时，从外周血淋巴细胞中分离总RNA，并使用定量聚合酶链反应（PCR）检测iNOS信使核糖核酸（mRNA）表达。在两种实验条件下，HR、收缩压（SBP）和舒张压（DBP）均升高（P<0.05），暴露模式无差异，且3天内无促进作用的证据。比较暴露前后的值时，IH或CH期间iNOS mRNA无显著变化。然而，在第3天结束时，IH暴露第1-3天的iNOS表达与平均暴露结束时的DBP（r=-0.79）和平均血压（MBP；r=-0.76）呈负相关（P<0.05），而CH暴露则无此相关性。结论是，IH和CH均与显著但相当的血流动力学变化有关。BP与iNOS mRNA在IH暴露而非CH暴露时有负相关，这可能提示对两种暴露模式的血流动力学反应存在差异调节。
