早产大鼠高氧肺损伤组织还原型烟酰胺腺嘌呤二核苷酸脱氢酶的动态表达及其意义

Temporal Expression of Reduced Nicotinamide Adenine Dinucleotide Dehydrogenase in Lung of Premature Rats with Hyperoxia-Induced Lung Injury

目的探讨还原型烟酰胺腺嘌呤二核苷酸(NADH)脱氢酶亚单位1、2、5在早产大鼠高氧肺损伤组织中的动态表达及其意义。方法早产新生大鼠生后1d随机分为高氧和空气组,高氧组持续暴露于850mL/L氧气中,空气组置同一室内常压空气中。分别取二组大鼠高氧或空气暴露后1、4、7、10和14d肺组织标本,采用HE染色观察肺组织形态学改变,采用RT-PCR法在mRNA水平检测NADH脱氢酶亚单位1、2、5的表达。结果1.高氧暴露1、4d,早产大鼠肺组织形态较空气组无明显改变;高氧暴露7、10d,肺组织渐出现小血管充血扩张,肺泡腔内炎性细胞浸润,肺泡间隔增厚,肺泡数目减少、结构简单化和囊泡化等改变。2.空气组NADH脱氢酶亚单位1(ND1)和亚单位2(ND2)mRNA的表达随日龄增长渐降低,至7d时最低,随后其表达逐渐增高;空气组NADH脱氢酶亚单位5(ND5)mRNA的表达随日龄增长渐降低,至4d时最低,随后其表达逐渐增高。3.与同时间点空气组相比,高氧暴露后1、4和7dND1和ND5mRNA表达显著增强(Pa<0.05),随后其表达渐下降,10、14d时低于空气组,但二者相比差异无显著性意义(Pa>0.05);与同时间点空气组相比,高氧暴露后1、4d ND2 mRNA表达二组间差异无显著性意义(Pa>0.05),7d时较空气组极显著增强(P<0.01),10、14d时较空气组显著降低(Pa<0.05)。结论高氧可导致早产大鼠肺组织NADH脱氢酶表达改变,提示其可能参与高氧肺损伤的病理生理过程。

Objective To explore the temporal expression of reduced nicotinamide adenine dinucleotide（NADH） dehydrogenase subunit 1, 2,5 in lung of premature rats with hyperoxia - induced lung injury and its significance. Methods Premature Sprague - Draw rats were randomly assigned to hyperoxia group and air group at 1 d after birth. These rats in hyperoxia group were persistently exposed to 850 mL/L oxygen and those in air group to room air. The lung tissues of both groups were collected at 1,4,7,10 and 14 d after being exposed to hyperoxia or air. The lung histological changes were observed by HE staining, and the expression of NADH dehydrogenase subunit 1,2,5 mRNA were detected by semi -quantitative reverse transcription polymerase chain reaction （ RT - PCR）. Results 1. There were no lung histological changes in hyperoxia group before the 4 d after being exposed to hyperoxia,then the lung in hyperoxia group gradually existed a series pathological histological changes. 2. The expressions of NADH dehydmgenase subunit 1 （ND1） and subunit 2 （ND2） mRNA in air group gradually decreased with age, the lowest at 7 d ,then it gradually increased ; the expression of NADH dehydmgenase subunit 5 （ ND5 ） mRNA in air group gradually decreased with age, the lowest at 4 d, then it gradually increased. 3. Compared with air group, the ND1 and ND5 mRNA levels in hyperoxia group were significantly higher （ Pa 〈 0.05 ） at 1,4 and 7 d, then it gradually decreased, lower than air group at 10 and 14 d, but there was no significant difference （Pa 〉 0.05 ） ;compared with air group, the ND2 mRNA level in hypemxia group had no obvious changes at 1 and 4 d, increased significantly at 7 d （ P 〈 0.05 ）, and then decreased significantly at 10 and 14 d （Pa 〈 0.05 ）. Conclusion Hyperoxia induces the expression of NADH dehydrogenase in premature rat lung,this indicates that this may participate in the physiological and pathology processes of hyperoxia- induced lung injury.