TGF-β_1诱导肺泡上皮细胞间质转化

TGF-β_1 induced epithelial-mesenchymal transition of alveolar epithelial cells

目的:通过观察TGF-β1诱导下A549细胞出现的细胞形态学和E-cad表达的变化,探讨上皮细胞-间质细胞转化(epithelial-mesenchymal transition,EMT)过程在肺纤维化发病机制中的作用。方法:体外培养A549细胞,以TGF-β1进行干预,收集不同时段的细胞,应用荧光实时定量PCR(RT-PCR)检测TGF-β1干预前后E-cad的mRNA表达变化;倒置相差显微镜观察细胞形态学的变化;间接免疫荧光观察E-cad蛋白表达的变化。结果:倒置相差显微镜观察到TGF-β1干预后A549细胞由鹅卵石状变为梭形,形态如同肌纤维母细胞。间接免疫荧光显示A549细胞的E-cad表达(红色荧光染色)随时间延长逐渐减少。RT-PCR显示E-cad的mRNA表达下调(P<0.05)。结论:TGF-β1在体外诱导肺泡上皮细胞向间质细胞转化,肺泡上皮细胞间质转化是肺纤维化的重要发病机制之一。

Objective By observing the cellular morphology changes and the expression of E-cad after A549 cells were treated with transforming growth factorβ1 （ TGF-β1 ） ,to investigate the role of epithelial-mesenchymal transition （ EMT） in the pathogenesy of pulmonary fibrosis.Method A549 cells cultured in vitro were treated by TGF-β1 ,then harvested at different time points to assay mRNA expression of E-cad by real-time PCR （ RT-PCR） before and after A549 cells being treated by TGF-β1.Cellular morphology changes were observed by phase-contrast microscope.Protein expression of E-cad by indirect immunofluorescence.Results After being treated by TGF-β1 ,A549 cells were observed by inverted phase contrast microscope to turn from pebble shape to fusiform shape,a myofibroblast-like morphology.Indirect immunofluorescence showed protein expression of E-cad reduced as time went by（ red stain） .The mRNA expression of E-cad was down-regulated in RT-PCR（ P 0.05） .Conclusion TGF-β1 induced EMT of alveolar epithelial cells in vitro suggests that EMT of alveolar epithelial cells might be one of fundamental mechanisms of pulmonary fibrosis.