宫内炎性暴露对胎鼠及早产大鼠肺细胞凋亡及肺Bax和Bcl-2基因表达的影响

Effect of intrauterine inflammatory expose on apoptosis of pneumonocytes and pulmonary Bax gene and Bcl-2 gene expressions in fetal rats and premature rats

目的：观察宫内炎性暴露对胎鼠及早产大鼠肺细胞凋亡及肺Bax和Bcl-2基因表达的影响,探讨其与新型支气管肺发育不良（BPD）发病机制之间的关系。方法：定期受孕的Sprague Dawley（SD）大鼠随机分为脂多糖（LPS）组和生理盐水组（对照组）,于孕15天羊膜腔内注射LPS/无菌生理盐水。两组动物均于胚胎19天（E19）及出生后第1、3、5、7天（P1、P3、P5、P7）各随机取8只,应用脱氧核糖核酸转移酶介导的细胞凋亡标记技术（TUNEL）原位检测细胞凋亡及逆转录-聚合酶链反应技术（RT-PCR）检测各组肺组织Bax和Bcl-2 mRNA表达水平。结果：LPS组随鼠龄递增,肺细胞凋亡数目逐渐增加,至P3达高峰,P5后逐渐下降;在E19-P7均高于对照组,且在E19、P1及P3与对照组相比差异有统计学意义（P〈0.05）;LPS组Bax mRNA的表达在E19-P7均高于对照组,且在E19-P5与对照组相比差异有统计学意义（P〈0.05）;Bcl-2 mRNA的表达LPS组在E19-P7均较对照组低,且在E19-P5与对照组相比差异有统计学意义（P〈0.05）。结论：宫内炎性暴露可能通过调控Bax/Bcl-2的表达使肺组织细胞过度凋亡,进而导致新型BPD的发生。

Objective： To observe the effect of intrauterine itfflammatory expose on apoptosis of pneumonocytes and pulmonary Bax gene and Bcl -2 gene expressions in fetal rats and premature rats, explore its relationship with pathogenesis of bronchopulmonary dysplasia （BPD） . Methods： Timed pregnant Sprague Dawley （SD） rats were randomly divided into lipopolysaccharide （LPS） group and normal sa- line group （ control group） . The rats in the two groups were treated with amniotic cavity injection of normal saline and LPS, respectively on the fifteenth day during pregnancy. Eight rats were randomly selected from the two groups on the nineteenth day during embryonic period and the first day, the third day, the fifth day and the seventh day after birth. TUNEL was used to detect cell apoptosis and RT- PCR was used to detect the expression levels of pulmonary Bax mRNA and Bcl - 2 mRNA in the two groups. Results ： The apoptotic number of pulmonary cells increased gradually with increase of age in LPS group, which peaked on the third day after birth, then decreased gradually from the fifth day; the apoptotic numbers of pulmonary ceils on the nineteenth day during embryonic period and the first day, the third day, the fifth day and the seventh day after birth in LPS group were higher than those in control group, and there were statistically significantly differences on the nineteenth day during embryonic period and the first day, the third day after birth between the two groups （P 〈 0. 05 ） ; the expression levels of Bax mRNA on the nineteenth day during embryonic period and the first day, the third day, the fifth day and the seventh day after birth in LPS group were higher than those in control group, and there were statistically significantly differences on the nineteenth day during embryonic period and the first day, the third day, the fifth day after birth between the two groups （P 〈 0. 05 ） ; the expression levels of Bcl - 2 mRNA on the nineteenth day during embryonic period and the first day, the third day, the fifth day and the seventh day afterbirth in LPS group were lower than those in control group, and there were statistically significantly differences on the nineteenth day during embryonic period and the first day, the third day, the fifth day after birth between the two groups （ P 〈 0. 05 ） . Conclusion ： Intrauterine inflammatory expose may induce excessive apoptosis of pulmonary cells by regulating Bax/Bcl- 2 expression, which may contribute to the occurrence of BPD.