Wnt7b在Nitrofen诱导的先天性膈疝大鼠模型胎肺中的表达

The expression of Wnt7b in fetal lungs of rat models of congenital diaphragmatic hernia induced by nitrofen

目的研究Wnt7b在Nitrofen诱导的先天性膈疝（congenital diaphragmatic hernia，CDH）胎肺中的表达特点，探讨其在CDH肺发育不良发生机制中的可能作用。方法采用实时荧光定量PCR方法检测Wnt7b基因在妊娠E17．5、E19．5、E21．5的Nitrofen诱导CDH大鼠模型胎肺及正常对照大鼠胎肺中的相对表达量，并用免疫组化方法检测wnt7b蛋白在胎肺中的表达。结果正常对照组和CDH组胎肺中Wnt7b mRNA的表达水平均随着胎龄的增加呈下降趋势，其中E17．5胎龄CDH组胎肺中Wnt7bmRNA的表达水平与对照组相比，差异无统计学意义；而E19．5、E21．5胎龄CDH组胎肺中wnt7b mRNA的表达水平高于对照组，差异有统计学意义（P〈（）．05）。对E21．5胎龄对照组和CDH组的标本进行免疫组化检测，结果显示wnt7b免疫阳性细胞主要分布在支气管和细支气管上皮，且CDH组Wnt7b免疫阳性程度（以平均光密度值表示）较正常对照组升高，有统计学差异。结论Wnt7b mRNA表达量随大鼠胎肺逐渐发育成熟而下降，提示其在胎肺中的表达量与胎肺发育的成熟度有关。CDH组中E19．5、E21．5胎龄时Wnt7b mRNA的表达水平明显高于对照组，是CDH孕晚期胎肺发育滞后的分子基础之一，提示Wnt7b在CDH孕晚期胎肺中表达增高可能参与了肺发育不良。Wnt7b蛋白在肺发育中特异性定位于气道上皮，提示信号可能在肺上皮与间质细胞之间有重要联系，协同促进上皮和问质的发育。

Objective To investigate the Wnt7b expression in fetal lungs of rat models of con genital diaphragmatic hernia（CDH） induced by nitrofen and to investigate the role of Wnt7b in the formation of pulmonary dysplasia in the process of CDH. Methods The expression of Wnt7b mRNA were detected in different developmental stages （E17. 5, E19. 5 and E21.5） in fetal lungs of rat model of CDH and in lungs of normal rats by Real time Quantitative RT-PCR. The expression of Wnt7b protein in rat fetal lungs were detected by immunohistochemistry. Results The relative quantities of Wnt7b mRNA in the fetal lungs decreased during E17. 5, E19. 5 and E21.5 both in normal group and CDH group. The Wnt7b expression was significantly higher in lungs at E19. 5 and E21.5 in lungs of nitrofen-treated rats than that in normal lungs, while at E17.5, no significant difference were noted between both groups, hnmunohistochemical staining showed that Wnt7b was expressed predominantly in the airway epithelia. The immunological activity （shown by the average optical density） in CDH group was higher than that in the control group. Conclusions The Wnt7b mRNA expression decreases gradually with development of fetal lungs, which may indicate that Wnt7b mRNA probably associates with the maturity of fetal lungs. The relatively increased level of Wnt7b mRNA in CDH group at the late gestation may be the molecular basis of pulmonary dysplasia in rat models of CDH. The exclusive expression of Wnt7b in the airway epithelia indicates that Wnt7b signaling pathway may he important between epithelia and mesenchymal, which suggests that Wnt7b can improve the concordant development of epithelia and mesenchymal.