慢性缺氧对左向右分流型先天性心脏病大鼠肺循环及生长发育的影响

The effect of chronic ischemia on the pulmonary circulation and development of rats with congenital left-to-right shunt heart diseases

目的探讨慢性缺氧对左向右分流型先天性心脏病大鼠肺循环及生长发育的影响。方法选40只SD大鼠,体重(122.6±12.5)g。随机分为分流组和对照组,每组20只;再按不同氧浓度分为常氧组(21%O2)、低氧组(12%O2),每组10只。分流组行套管法右颈总动脉-颈外静脉分流术,每日记录大鼠体重增长情况,术后6周进行Morris水迷宫实验评估学习及认知能力,导管法测量肺动脉平均压(mPAP)、主动脉平均压(MAP),HE染色观察肺小动脉中层增厚情况并测量右心室肥厚程度。结果对照组中低氧组大鼠体重增长显著低于常氧组[(201±19)gvs.(232±11)g,P<0.01],低氧分流组最显著[(150±21)gvs.(232±11)g,P<0.01]。Morris水迷宫试验中,定位实验常氧对照组及分流组大鼠escapelatency时间较低氧组显著缩短;记忆实验中各组大鼠表现与定位实验相似。低氧及分流均可造成大鼠mPAP升高、肺小动脉中膜厚度百分比(MT%)增高及右心室肥大指数(RVHI),低氧分流组大鼠升高最显著(27.62±3.09vs.9.79±0.97,68.96±9.68vs.25.27±4.18,0.33±0.05vs.0.28±0.03,P均<0.01);低氧组大鼠动脉血气HCT显著升高、动脉氧分压(PaO2)下降较常氧组明显,低氧分流组最显著(59.0±7.2vs.40.9±3.6,65.0±6.9vs.95.0±3.9,P<0.01)。结论缺氧可加重左向右分流大鼠生长迟缓、学习记忆能力降低,导致肺循环的损害。

Objective To study the affect of chronic ischemia on pulmonary circulation and growth development in rats with left to right shunt heart diseases. Methods Forty male SD rats were randomly divided into the control group and the shunt group, and each group were divided into 21%O 2 group and 12%O 2 group. Rats in the shunt group received right common carotid artery-external jugular vein shunt operation with a subtile cuff. The weight of rats was recorded every day. At the 6th week, the ability of learning and spatial localization on rats were tested by Morris water maze. Six weeks after operation, all rats were observed by pulmonary haemodynamic measurements with catheterization and pathologic detection were performed to assess right ventricular hypertrophy and pulmonary vascular remodeling （PVR）. Results Weight gain and the ability of learning and spatial localization were obviously decreased in 12% O 2 group as compared with those of 21%O 2 group （201±19 vs. 232±11,P 〈 0.01）. In 12%O 2 group, the mPAP, MT% and RVHI were gradually increased when compared with 21%O 2 group （P 〈 0.01）, especially in shunt with 12%O 2 group （27.62±3.09 vs. 9.79±0.97, 68.96± 9.68 vs. 25.27±4.18, 0.33±0.05 vs. 0.28±0.03,P 〈 0.01）. In 12%O 2 group, the HCT increase and PaO 2 decrease were more evident when compared with 21% O 2 group （P 〈 0.01）. Conclusion Hypoxia could impair weight gain and the ability of learning and spatial localization and cause injury to pulmonary circulation and right ventricular in SD rats.