microR-146a、microR-29a在新生大鼠急性肺损伤中的动态表达

Dynamic expression changes of microR-146a and microR-29a in neonatal rats with acute lung injury

目的 观察脂多糖（LPS）诱导的新生大鼠急性肺损伤（ALI）肺组织中 microRNA（miR）-146a、miR-29a的动态表达变化，探讨其对ALI的作用。方法 选取7 d龄新生 SD 大鼠80只，简单随机法分为LPS组和对照组。LPS组大鼠腹腔注射内毒素（5 mg/kg）建立新生大鼠 ALI模型；对照组大鼠腹腔注射9 g/L盐水0.1 mL。分别于6 h、1 d、3 d、7 d留取新生大鼠肺组织及血清标本，观察肺组织病理变化，酶联免疫吸附试验测定血清中肿瘤坏死因子-α（TNF-α）的变化，反转录-聚合酶链反应法检测肺组织中 miR-146a和 miR-29a的相对表达量。结果 苏木精-伊红染色显示 LPS组大鼠肺组织呈ALI表现，血清中 TNF-α 和肺组织中 miR-146a的表达水平较对照组呈高表达趋势（P 〈0.05），miR-29a较对照组呈低表达趋势（P 〈0.05）。结论 miR-146a和miR-29a的差异性表达在ALI中有重要作用，其关键靶点可能为临床早期诊治ALI及新药的研发提供新的标靶。

Objective To observe the dynamic expression changes of microRNA （miR）-146a and miR-29 in neonatal rats with acute lung injury （ALI） induced by lipopolysaccharide （LPS）, and to explore their influence on ALI. Methods Totally 80 newborn rats aged 7 days were randomly assigned into the LPS group and control group. Intraperitoneal injection of endotoxin（5 mg/kg） was done to establish neonatal rat model of ALI in the LPS group. Rats in the control group were intraperitoneally injected with 0.1 mL 9 g/L saline. Lung tissue and blood specimens from new- born rats were taken at 6 hours, 1 day, 3 days and 7 days after treatment. Lung pathological changes were observed, and the levels of serum tumor necrosis factor-alpha （ TNF- α） were detected by enzyme-linked immunosorbent assay. The relative expressions of lung tissues miR-146a and miR-29a were determined by reverse transcription-polymerase chain reaction. Results The lung tissue hematoxylin-eosin staining indicated ALI in the LPS group. Compared with the con- trol group,the levels of serum TNF- α and lung tissue miR-146a showed high expression （P 〈 0. 05 ） , while the miR-29a was significantly reduced （P 〈 0.05 ）. Conclusions Differential expressions of miR-146a and miR-29a have an important role in neonatal rat ALI. The key targets may provide new targets for early clinical diagnosis and treatment of ALI, as well as research and development of new medicine.