持续吸入低浓度氧对新生大鼠肺发育相关因子的影响

Effects of prolonged exposure to low concentration oxygen on expression of growth factors associated with lung development in neonatal rats

目的探讨持续吸入低浓度氧对新生大鼠肺发育相关因子，包括血管内皮生长因子（vascular endothelial growth factor，VEGF）及其受体1（VEGF receptor-1，VEGFR1）、受体2（VEGF receptor-2，VEGFR2）和转化生长因子-β1（transforming growth factor-β1，TGF—β1）表达的影响。方法新生足月SD大鼠16只，随机分为对照组和实验组，每组8只。实验组生后12h开始持续吸入氧气，氧浓度为30％。对照组吸入空气。于实验开始后21d处死实验大鼠，留取肺组织标本，HE染色观察病理改变，免疫组织化学法检测肺组织VEGF、VEGFR1、VEGFR2和TGF-β1蛋白表达，逆转录-聚合酶链反应技术检测其mRNA表达。组间比较采用t检验。结果与对照组相比，实验组肺组织无明显病理改变；实验组新生大鼠肺组织VEGF、VEGFR1、VEGFR2和TGF—β1蛋白平均累积吸光度分别为30．2±5．0、14．2±2．6、20．8±3．7和5．7±2．1，与对照组（分别为30．8±6．4、15．6±3．4、21．7±4．5和5．5±2．1）比较差异没有统计学意义（P均〉0．05）；实验组VEGF、VEGFR1、VEGFR2及TGF-β1 mRNA分别为对照组的1．6倍、1．6倍、2．1倍和1．1倍，差异也没有统计学意义（P〉0．05）。结论长时间吸入低浓度氧对新生大鼠肺发育影响不明显。

Objective To study the effects of prolonged exposure to low concentration oxygen on the expression of vascular endothelial growth factor（VEGF）, its receptors （VEGF receptor-1, VEGFR1 and VEGF receptor-2, VEGFR2）and transforming growth factor-β1 （TGF-β1） in the lungs of neonatal rats. Methods Sixteen SD rat pups were divided randomly into control group and experiment group with 8 pups in each. Rats in the experiment group were placed in 30% oxygen from 12 h postnatal while control group in air. The rats were sacrificed at postnatal day 21 and their lungs were collected. The lung sections were stained with hematoxylin-eosin for histological evaluation. Immunohistochemistry and reverse transcription-polymerase chain reaction（RT-PCR） were used to detect the protein and mRNA expression of VEGF, VEGFR1, VEGFR2 and TGF-β1 in rat lungs. Results There was no pathological change in the experimental group compared with the control. No differences were found between experiment the and control group in the protein expression of VEGF （30.2±5.0 vs 30.8±6.4）, VEGFR1 （14. 2±2.6 vs 15.6±3.4）, VEGFR2（20.8±3.7 vs 21.7± 4. 5） and TGF-β1（5.7±2.1 vs 5.5±2.1） （P〉0. 05）,neither in the mRNA expression of VEGF（1.6 vs1. 0）, VEGFR1（1.6 vs 1.0）, VEGFR2（2.1 vs 1.0） or TGF-β1（1.1 vs 1.0） （P〉0.05）. Conclusions Prolonged oxygen exposure at low concentration in neonatal rats may not affect their lung development remarkably.