Notch2、Notch4在大鼠早期肺发育过程中的动态表达

Dynamic Expressions of Notch2, Notch4 in the Early Stages of Lung Development in Rat

目的探讨Notch2、Notch4在SD大鼠肺发育过程中的作用。方法取孕18、202、1 d胎鼠和孕21 d早产鼠(足月为22 d)生后1、7、14、21 d肺组织标本(n=8),HE染色,进行组织形态学观察、免疫组织化学法和半定量RT-PCR法检测Notch2、Notch4的表达。结果孕龄18 d的胎肺见支气管树分支形成,间质中毛细血管毗邻呼吸道分布;20 d至早产生后1 d时,肺组织基本结构为终末囊泡,上皮分隔进一步发展,间质减少,毗邻上皮的毛细血管增多;7、14 d肺泡数目增多并渐成熟,气血屏障变薄;21 d肺泡壁进一步变薄,间质细胞少见。免疫组织化学结果显示,Notch2在孕182、0 d即有表达,21 d表达最强,出生后表达逐渐减弱;Notch4在孕18 d表达最明显,以后呈减弱趋势。RT-PCR检测Notch2、Notch4 mRNA变化与多肽变化规律相似。结论Notch2、Notch4参与大鼠早期肺发育过程。

Objective To explore the roles of Notch2, Notch4 in the early stages of lung development in rats. Methods Lung specimens from 18 d,20 d,21 d fetuses and 1 d,7 d, 14 d and 21 d preterm Sprague Dawley rats of day 21 of gestation（term rat of day 22 of gestation） were used（ n = 8）. Tissue specimens were used to evaluate the lung histological changes by HE staining, the expressions of Notch2, Notch4 by immunohistochemistry and the level of mRNA by reverse transcription polymerase chain reaction（RT-PCR）. Results Lungs of 18 d fetuses the major airways developed centrifugally, blond capillaries began to appose to air ways; lungs of 20 d, 21 d fetuses and of 1 d preterm rats. Sac - llke end segrnents showed progressive thinning of the epithelial linings, lungs were canalized with the multiplication of capillaries,and the cellularity of the interstitium dgcreased markedly with age; lungs of 7 d, 14 d preterm rats the number of alveoli increased and became mature, the thiekness of the blond- air barrier became thinner and thinner; 21 d the alveoll septal was relatively thin at postnatal 21 d and with few interstitial cells, The expression of Notch2 was strongest at gestation 21 d, then became weaker till postnatal 21 d, It became weakest. Notch4 exhibited significant differences between gestational 18 d and the other days（ P 〈 0.05 ）, then were gradually weakened to trace. Relative abundance of Notch2, Notch4 were similar to the expression of their polypeptides. Conclusion Notch2, Notch4 play important roles during the early stages of lung development.