中文摘要：

本研究旨在探讨并比较慢性间歇性低压低氧（intermitten thypobaric hypoxia，IHH）和慢性连续性低压低氧（continuous hypobaric hypoxia，CHH）对大鼠血液动力学作用的影响。40只成年Sprague—Dawley大鼠随机分为5组：对照组（CON），28天IHH处理组（IHH28），42天IHH处理组（IHH42），28天CHH组（CHH28）和42天CHH组（CHH42）。IHH火鼠于低压氧舱分别接受28或42天模拟5000m海拔高度低氧（11．1％O2）处理、每天6h。CHH处理大鼠生活在低压氧舱环境中，除每天半小时常氧供食、供水和清洁外，其余时间均分别接受时程为28或42天的模拟5000m海拔高度低氧（11．1％O2）处理。每周定时测定大鼠体重。通过导管法测定基础常氧和急性低氧状态下的血液动力学，包括半均动脉压（meanartery blood pressure，MAP）、心率（heartrate，HR）、左审收缩峰压（1eft ventricular systolic pressure，LVSP）、正负左率最人压力变化速率（maximum change rate of left ventricular pressure，±LVdP／dtmax）。通过生物化学方法测定大鼠心肌超氧化物岐化酶活性和丙二醛含量。并分别测定全心、左心室和右心室重量。结果显示：（1）CHH42大鼠基础HR和MAP低于CON，IHH和CHH28大鼠（P〈0．05）。（2）IHH大鼠表现出明显的抗心肌缺氧／复氧损伤作用，表现为急性低氧状态下的HR、MAP、LVSP和＋LVdP/dtmax，改变明显低于CON大鼠（P〈0．05）；CHH大鼠表现出更为明显的抗急性低氧心脏保护作用，表现为急性低氧的HR、MAP、LVSP和±LVdP/dtmax；改变明显低于CON和IHH火鼠（P〈0．05），但出现复氧损伤作用，表现为复氧过程中血液动力学的恢复明显低于CON和IHH大鼠（P〈0．05）。（3）与CON大鼠相比较，IHH和CHH大鼠心肌抗氧化能力明显增强（P〈0．05，P〈0．01）。（4）与IHH和CON大鼠相比较，CHH大鼠表现明显的右心室肥厚（P〈0．01）。结果表明，IHH可?

英文摘要：

The aim of this study is to investigate the effects of chronic intermittent hypobaric hypoxia （IHH） and chronic continuous hypobaric hypoxia （CHH） on hemodynamics under basic normoxia and acute hypoxia conditions and to find the difference of two types of chronic hypoxia. Forty adult male Sprague-Dawley （SD） rats were randomly divided into 5 groups： Control group （CON）, 28 days IHH group （IHH28）, 42 days IHH group （IHH42）, 28 days CHH group （CHH28） and 42 days CHH group （CHH42）. The rats in IHH groups were treated with intermittent hypoxia （11.1% 02） mimicking 5 000 m altitude in a hypobaric chamber for 28 or 42 d, 6 h a day, respectively. The rats in CHH groups lived in the hypobaric chamber with the same degree of hypoxia like IHH rats except half an hour in normoxia each day for feeding and cleaning. The body weight of rats was measured once a week. The parameters in hemodynamics, such as mean artery blood pressure （MAP）, heart rate （HR）, left ventricular systolic pressure （LVSP）, maximum change rate of left ventricular pressure （＋LVdP/dtmax） were recorded under basic normoxia and acute hypoxia conditions through catheterization technique. The superoxide dismutase （SOD） activity and malondialdehyde （MDA） content in myocardium of rats were measured by biochemical method. The weights of whole heart, left and right ventricles were measured separately. The results showed： （1） The basic HR and MAP in CHH42 rats were lower than those in CON, IHH and CHH28 rats （P〈0.05）. （2） IHH showed a cardioprotection against acute hypoxia and reoxygenation injury, manifested as the result that the changes of HR, MAP, LVSP, and ±LVdP/dtmax were smaller than those in CON rats during acute hypoxia and reoxygenation. CHH showed a rather strong cardioprotection during acute hypoxia, manifested as the result that the decreases of HR, MAP, LVSP, and ±LVdP/dtmax were much smaller, but it did damage during reoxygenation, manifested as the result that the rec