【摘要】 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。更多还原

【Abstract】 Objective To explore the roles of Notch2,Notch4 in the early stages of lung development in rat.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,blood capillaries began to appose to air ways;lungs of 20 d,21 d fetuses and of 1 d preterm rats.Sac-like end segments showed progressive thinning of the epithelial linings,lungs were canalized with the multiplication of capillaries,and the cellularity of the interstitium decreased markedly with age;lungs of 7 d,14 d preterm rats the number of alveoli increased and became mature,the thickness of the blood-air barrier became thinner and thinner;21 d the alveoli 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.更多还原