高氧及TGF-β1对肺泡Ⅱ型细胞上皮间质转化的影响

Effect of hyperoxia and TGF-β1 on epithelial-mesenchymal transition of typeⅡ alveolar epithelial cells

目的:探讨高氧及TGF-β1干预小鼠肺泡Ⅱ型细胞(AECⅡ)后,是否发生上皮间质转化(EMT)及其影响。方法:小鼠肺泡Ⅱ型细胞系MLE-12,随机分为空气暴露组、高氧暴露组、TGF-β1干预空气暴露组、TGF-β1干预高氧暴露组。观察各组6、12、24、48 h细胞形态变化。应用细胞免疫荧光双标法及荧光定量PCR法检测各组各时间点肺表面活性物质B(SP-B)及成纤维细胞特异性蛋白1(FSP1)蛋白和mRNA的表达情况。结果:随着高氧及TGF-β1干预时间的延长,AECⅡ逐渐由鹅卵石样变成纺锤体形状,获得成纤维细胞样外观。同时,AECⅡ特异性标记SP-B表达逐渐减弱,成纤维细胞特异性标记FSP1表达逐渐增强,24 h时两者时可见明显的共表达。高氧暴露组、TGF-β1干预空气暴露组及TGF-β1干预高氧暴露组24、48 h SP-B mRNA表达较同时间空气暴露组下调,而FSP1 mRNA表达较同时间空气暴露组上调。结论:高氧及TGF-β1均能诱导AECⅡ发生上皮间质转化,且两者对EMT的作用具有时间依赖性。

AIM： To investigate the effect of hyperoxia and TGF-β1 on epithelial-mesenchymal transition （EMT） of type Ⅱ alveolar epithelial cells （ AEC- Ⅱ ） of mice. METH. ODS= AEC-Ⅱ cells （MLE-12 lines） were randomly divided into following groups; air exposure group, hyperoxia expo- sure group, air exposure combined with TGF-β1 treatment group, hyperoxia exposure combined with TGF-β1 treatment group. The morphological changes of cells in each group were observed at 6, 12, 24, 48 hours. The protein and mR- NA expressions of AEC Ⅱspecific marker lung surfactant protein B （SP-B）and fibroblast specific marker fibroblast specific protein （ FSP1 ） were detected by double-labeled immunoflu orescence and real time-PCR at the same time point, respectively. RESULTS： Along with the time of expo- sure to hyperoxia and TGF-β1, AEC Ⅱ cells gradually changed from pebble-like shape to spindle shape, and showed some flbroblast appearances. Synchronously, the protein expression of SP-B in AEC Ⅱ cells decreased, whereas the expression of FSP1 increased. The co-expressed were observed at 24 hours. Comparing with that of the air exposure group, the mRNA expression of SP- B in the hyperoxia exposure group, air exposure combined with TGF-β1 treatment group, hyperoxia exposure combined with TGF-β1 treatment group decreaseed significantly,whereas the mRNA expression of FSP1increased signifi- cantly at 24 hours and 48 hours （P〈0.01）. CONCLUSION： Hyperoxia and TGF-β1 can induce EMT of type Ⅱ alveolar epithelial cells in a time-dependent manner.