间歇低氧对大鼠血管内皮硫氧还蛋白的影响

Study on thioredoxin in vascular system of rats exposed in different degree of chronic intermittent hypoxia

目的通过测定睡眠呼吸暂停模式间歇低氧大鼠血管内皮硫氧还蛋白（thioredoxin，TRX）mRNA的表达水平，进一步探讨氧化应激在阻塞性睡眠呼吸暂停综合征导致高血压发生机制中的具体作用。方法160只成年雄性wistar大鼠随机分为5组：5％间歇低氧组，7．5％间歇低氧组，10％间歇低氧组，10％持续低氧对照组和常氧对照组，给予相应低氧暴露，共8周，分别于第2周、第4周、第6周和第8周末从每组中各随机抽取8只大鼠解剖取主动脉组织，采用realtimePCR法测定动脉内皮硫氧还蛋白mRNA的表达水平。结果间歇低氧暴露后大鼠动脉收缩压明显增高，各间歇低氧组暴露第4周、第6周和第8周时明显高于实验前水平及同一时间点10％持续低氧对照组和常氧对照组（Pd0，05）。随暴露时间延长，各间歇低氧组内皮TRXmRNA表达水平逐渐增加，其中5％间歇低氧组最为明显，暴露第6周时，5％间歇低氧组TRXmRNA表达水平显著高于10％持续低氧对照组、常氧对照组及10％间歇低氧组（P〈O．01）；暴露第8周时，5％间歇低氧组显著高于常氧对照组（P＜0．01）和10％间歇低氧组（P〈o．05）。结论睡眠呼吸暂停模式间歇低氧可导致血管内皮系统TRXmRNA的表达水平增加，其增加程度与间歇低氧程度有关，表明TRX在慢性间歇低氧导致的血管系统的损伤过程中具有重要作用。

Objective To approach the possible role of oxidative stress in pathogenesis of hypertension caused by obstructive sleep apnea syndrome, we detected the mRNA expression of thioredoxin（TRX） in aortic endothelial system of rats exposed in different degree of intermittent hypoxia. Methods 160 Wistar rats were randomly assigned to 5 groups： 5% IH, 7.5% IH, 10~ IH, 10% continuous hypoxia and normoxia control groups. Selected 8 rats from each group randomly and killed on the second, fourth, sixth and eighth weeks respectively. Then detect the mRNA expression of TRX in aortic endothelial system by real-time PCR. Results On the fourth, sixth and eighth weeks, artery systolic blood pressure （SBP） of IH groups increased significantly compared with those before the experiment and those of CH and NC groups at the same time（ P 〈0.05）. With the extending of exposure time, the mRNA expression of TRX showed a rising trend, and the level in 5% IH were significantly higher than those of 10% IH, continuous hypoxia and control groups on the sixth weeks（ P〈0.01）. On the eighth weeks, the mRNA expression in 5% IH group was higher than those of NC group（ P〈0.01） and IH3 group （ P〈0.05）. Conclusions Intermittent hypoxia o{ obstructive sleep apnea mode could induce mRNA expression of TRX in endothelial system rising, which correlated with the degree of IH. It showed that TRX played critical role in the pathogenesis of cardiovascular diseases in chronic intermittent hypoxia.