维甲酸对高氧暴露下新生大鼠肺组织中Ⅰ型胶原含量的影响

study on retinoic acid-induced alteration of typeⅠcollagen content in lungs of hyperoxia-exposed newborn rats

为探讨维甲酸对高氧暴露下新生大鼠肺组织中Ⅰ型胶原含量的影响 ,将生后2d的SD大鼠随机分为4组 :①空气+生理盐水组 ;②高氧 +生理盐水组 ;③高氧 +地塞米松组 ;④高氧 +维甲酸组。②、③和④组持续暴露于85 %O2 中 ,于生后14d采用免疫组化和原位杂交方法对肺组织中Ⅰ型胶原蛋白、转化生长因子βⅠ、Ⅱ型受体、肺组织中Ⅰ型胶原mRNA行定位、半定量检测 ,作HE染色行辐射状肺泡计数。结果显示 ,与高氧 +生理盐水组相比 ,高氧 +维甲酸组辐射状肺泡计数显著增加 ,肺组织中Ⅰ型胶原蛋白表达明显增强 ,而Ⅰ型胶原基因表达和转化生长因子βⅠ、Ⅱ型受体表达显著减弱 ,阳性表达明显改变的分布主要在支气管上皮细胞、肺泡上皮细胞和肺内间质细胞。提示维甲酸通过对Ⅰ型胶原mRNA转录后调控和调节Ⅰ型胶原蛋白的降解而增加肺内胶原含量 。

to explore the retinoic acid_induced effects on the typeⅠcollageN cOntent in the hyperoxia_exposed newˉborn rats lung,the newborn sprague_dawley RAts at age of2days were randomly divided into4groups:①air+normal saline;②hyperOxygen+normal saline;③hyperoxygen+dexamethasone;and④hyperoxygen+retinoic acid.Groups2,3and4were exposed to85%o 2 .lung collagenⅠ,transforming growth factorS(β 1 receptor andβ 2 receptor)and procollagen mrna level were examined at tHe age of14days with the immunohistochemical staining and in situ hybridization,While the lung development was analyzed with the radial alveoli count(rac).the results indicated that the rac was significantly reduced in the group4in comparIson with the lung from group3.retinoic acid could markedly increase the typeⅠcOllagen expression in lung,while the typeⅠcollagen gene and the transforming gRowth factorβ 1 andβ 2 receptors expression greatly reduced.the distribution oF the positive expression alteration was mainly located in the bronchial epithelIal cells,alveolar epithelial cells and the alveolar intersitium.suggesting thaT the increase in retinoic acid_associated lung collagen could be due to posttraNscriptional regulation and typeⅠcollagen degradation,so as to increase the luNg collagen content resulting in the inverse inhibition effect on the lung develOpment caused by hyperoxygen.