持续吸入不同浓度氧气对新生大鼠肺血管内皮生长因子及其受体mRNA表达的影响

Effects of prolonged oxygen exposure at different concentrations on expressions of vascular endothelial growth factor and its receptors mRNA in pulmonary tissues of neonatal rat

目的探讨持续吸入不同浓度氧气对新生大鼠肺血管内皮生长因子（vEGF）及其受体1（VEGFRl）和受体2（VEGFR2）mRNA表达的影响。方法新生足月SD大鼠32只，随机分为对照组和实验组。实验组生后12h开始持续吸入氧气，按不同的吸入氧浓度，将实验组又分为30％O2组、50％O2组和75％O2组。对照组吸入空气。每组8只。于实验开始后21d处死实验大鼠，取出右肺下叶，RT—PCR技术检测VEGF、VEGFRl和VEGFR2mRNA表达，根据2^-△△CT的计算方法，实验组基因表达差异用实验组相对于对照组基因表达量的倍数表示。结果与对照组相比，30％O2对新生大鼠肺VEGF及其受体mRNA表达无影响。75％O2组VEGFmRNA表达是对照组的0．48倍；50％O2组、75％O2组VEGFR1 mRNA分别为对照组的0．18倍和0．06倍；VEGFR2mRNA分别为对照组的0．22倍和0．10倍，差异均有统计学意义（P〈0．05）。结论长时间吸入低浓度氧对新生大鼠肺VEGF及其受体mRNA影响不明显，而持续吸人中等浓度及较高浓度氧可降低VEGF及其受体mRNA的表达。

Objective To study the effects of prolonged oxygen exposure at different concentrations on expressions of vascular endothelial growth factor （VEGF） and its receptors （VEGF receptor-1 ,VEGFR1 and VEGF receptor-2, VEGFR2 ） mRNA in lungs of neonatal rat. Methods Thirty-two SD rat pups were randomly divided into control and experimental group. Rats in the experimental group were further divided into three subgroups： 30%O2, 50% O2 and 75% O2 group. Each group had 8 rats. The rats were sacrificed at postnatal day 21 and their right lower lobes were collected. Expressions of VEGF, VEGFR1 and VEGFR2 mRNA were detected by RT PCR. Results There was no effect on VEGF, VEGFR1 or VEGFR2 mRNA expression in 30%O2 group. The expressions of VEGF mRNA in the 75% O2 group was 0. 48 times of the control （P〈0.05）. The expressions of VEGFR1 mRNA（P〈0.01） and VEGFR2 mRNA （P〈0.01） in 50^O02 and 75% O2 group were lower than those of control. Conclusions Prolonged exposure to moderate or high oxygen concentration may reduce the expression of VEGF and its receptors＇ mRNA in the lung tissues of neonatal rats.