维生素A缺乏对大鼠肺脏发育的影响

目的探讨维生素A缺乏（vitamin A deficiency，VAD）对大鼠肺脏发育的影响及其可能的机制。方法建立VAD大鼠模型，取出生后2周正常及VAD幼鼠肺脏，HE、Weigert染色分别观察其肺脏组织形态变化和弹力纤维变化；Image Pro Plus5．0软件做肺脏形态学定量分析，蛋白质免疫印记检测大鼠肺组织MMP-9及TIMP-1蛋白含量变化。结果①VAD组大鼠肺上皮细胞堆积，出现明显的肺气肿，并发弥散的间质性肺炎，肺组织弹力纤维显著减少；②VAD组大鼠肺MMP-9的蛋白质表达水平明显高于对照组，TIMP-1水平变化不大，MMP-9与TIMP-1的比值升高。结论VAD导致大鼠肺脏正常发育受损，肺脏组织形态异常，可能通过上调MMP-9的表达诱发大鼠肺气肿。

Effects of Vitamin A Deficiency on the Development of Lung in Rats

Objective The aim of this study was to investigate the effects of vitamin A deficiency（VAD） on the development of lung in infant rats and the possible mechanism. Methods A model of vitamin A deficiency in rats was established. At the 14th day after birth, the rats were sacrificed. Histological changes of the lung tissue were evaluated by HE staining and elastin by Weigert staining, respectively. Morphological assessment was performed with Image Pro Plus 5.0 software. The expression of protein of both matrix metalloproteinase-9 （MMP-9） and tissue inhibitor of metalloproteinase-1 （TIMP-1） in the lung tissue was detected by Western blotting. Results Pulmonary epithelial cells were accumulated. Interstitial pneumonia and severe diffuse emphysema were observed histologically in the lungs of VAD rats. Elastin staining showed that elastin in the lung parenchyma of VAD rats was reduced evidently. Compared with the normal group, the expression of MMP-9 in lung tissue in VAD group was markedly increased, but TIMP-1 was not changed significantly. Conclusion Our data provided evidence that VAD induces profound morphologic alterations in the lung parenchyma. VAD may up-regulate the expression of MMP-9 leading to development of emphysema in rats.