宫内炎性暴露对胎鼠及早产大鼠肺组织细胞增殖和p53基因表达的影响

Influence of Intra-Amniotic Endotoxin Exposure on Cell Proliferating and Expression of p53 Gene in Lung Tissue of Embryo and Preterm Rat

目的观察宫内炎性暴露对胎鼠及早产大鼠肺组织细胞增殖和p53基因表达的影响,探讨其与新型支气管肺发育不良(BPD)发病的关系。方法定期受孕的SD大鼠随机分为脂多糖(LPS)组和对照组。分别于孕第15天用微量加样器在其羊膜腔内注射LPS(40μg/L)5μL和等量无菌9g/L盐水。二组均于胚胎19d及出生第1、3、5、7天(E19、P1、P3、P5、P7)各随机取8只,采用免疫组织化学方法和反转录-聚合酶链反应技术检测肺组织细胞增殖性核抗原(PCNA)蛋白及p53mRNA表达水平。应用SPSS12.0软件进行统计学分析。结果对照组PCNA的表达在E19～P1随鼠龄增加表达逐渐减弱,至P5表达最弱,以后随鼠龄增加逐渐增多。LPS组PCNA在E19～P1随鼠龄增加逐渐减弱,至P1最弱,以后随鼠龄增加而逐渐升高,LPS组PCNA在E19～P3表达均低于对照组,差异具有统计学意义(Pa<0.05)。对照组p53mRNA表达,在E19～P5随鼠龄增加逐渐下降,以后逐渐上升;LPS组p53mRNAE19～P7均较对照组高,在E19～P1与对照组比较,差异有统计学意义(Pa<0.05)。结论宫内炎性暴露可能通过上调p53基因的表达,抑制胎鼠及早产大鼠肺组织细胞增殖,干扰正常的肺发育进程,进而导致BPD的发生。

Objective To observe the expressions of proliferating cell nuclear antigen（PCNA） and p53 gene in lungs of the embryo and preterm rats exposed to intra - amniotic endotoxin and to explore the relationship between the intrauterine inflammation and the pathogenesis of bronchopulmonary dysplasia（BPD）. Methods Scheduled pregnant Sprague Dawley rats were randomly divided into 2 groups： saline group and lipoplysaccharide（LPS） group. LPS（40 μg/L,5 μL） or saline was injected intra -amniotic into the bows on 15^tg gestational age day,respectively. The lungs from the 2 groups aged 19 embryonic day（ E19 ） and postnatal day 1,3,5,7 （P1, P3, P5, P7 ） were removed and dissected from the main bronchi for analysis. PCNA protein levels were measured by immunohistochemistry,total RNA was extracted by Trizol reagent from the frozen lung tissues. Lung p53 mRNA levels were measured by semi - quantitative reverse transcription polymerase chain reaction. The results were analyzed by SPSS 12.0 software. Results The contents of PCNA decreased along with the lung development from E19 to P5 in control group and from E19 to P1 in LPS group. However,in LPS group,it was significantly lower than that in the controls from E19 to P3 （P 〈 0. 05 ）. The mRNA content change of p53 increased from E19 to P7 in LPS group, and it was significantly higher than that in control groups from E19 to P1 （P 〈 0.05 ）. Conclusions Intrauterine inflammation may be related to the evolution of lung injury and may contribute to the pathogenesis of bronchopulmonary dysplasia by upgrated expressions of p53 gene.