TGF-β/Smad介导上皮细胞间质转化在气管移植后移植体狭窄中的机制研究

Mechanism of TGF-p/Smad Signaling Pathway Regulating Epithelial-mesenchymal Transition in Tracheal Stenosis after Transplantation

目的探讨TGF-β/Smad信号通路介导的上皮细胞间质转化在气管移植后移植体狭窄中的作用机制。方法将50只体重180~220 g雄性大鼠随机均分为2组,取未移植大鼠气管为对照组,实验组为经体重匹配的Wistar-SD大鼠行气管原位移植术后大鼠。两组分别于术后第3、7、10、14、35、90天处死大鼠,获取移植体标本。应用HE染色测量计算纤维化率检测气管狭窄程度;应用免疫组织化学染色检测移植体内上皮细胞间质转化相关分子上皮粘附分子（E-cadherin）、波形蛋白（vimentin）、平滑肌肌动蛋白（α-SMA）表达量以及移植体内上皮细胞间质转化信号通路磷酸化（p-Smad2/3）蛋白表达量和相关转录因子（ZEB1）、Snail1表达量。结果 HE染色示对照组气管纤维化率为0.171±0.020,移植组术后气管纤维化率显著高于对照组（0.537±0.013,P〈0.01）。免疫组织化学提示移植组术后移植体中vimentin表达阳性的上皮细胞显著增多（P〈0.05）,上皮细胞中E-cadherin表达量明显减少（P〈0.05）。移植组术后移植体内TGF-β1较对照组表达量明显增多（P〈0.05）,术后p-Smad2/3表达量较对照组明显增加（P〈0.05）,转录因子ZEB1、Snail1在移植体内高表达（P〈0.05）。结论气管移植后移植体在术后第3 d即出现狭窄,其狭窄的机制可能与上皮细胞间质转化有关,同时其受到TGF-β/Smad信号通路以及转录因子ZEB1、Snail1的调节。

Objective To investigate that the TGF- beta/Smad signaling pathway mediated epithelial mesenchymal transition（EMT） in trachea stenosis after transplantation.Methods 180-220 g male rats（n=50） were randomly divided into a control group and an experimental group.No surgical operation rats were in the control group.Tracheal transplantation rats（Wistar-SD rat） were in the experimental group.Graft specimens were obtained in rats on 3,7,10,14,35,90 days after operation.HE staining is used to explain the fibrosis degree of tracheal stenosis.The fibrosis degree of tracheal stenosis was detected by calculating the fibrosis rate.Immunohistochemical staining was used to detect transplanted tracheal,such as EMT related molecules E-cadherin,vimentin,alpha-SMA expression,p-Smad2/3 expression and transcription factor ZEB1,Snail1 expression in tracheal graft specimens.Results HE staining showed that the tracheal fibrosis rate of the control group was 0.171±0.020,fibrosis rate was 0.537±0.013（P〈0.01） on the third day after transplantation.The result of immunohistochemical staining showed that vimentin positive epithelial cells increased significantly（P〈0.05）.E-cadherin expression significantly reduced（P〈0.05）.Compared with the control group,TGF- beta expression increased（P〈0.05） in the experiment group.Compared with the control group,the expression of p-Smad2/3,the transcription factor ZEB1 and Snail1 significantly increased（P〈0.05） in the experiment group.Conclusion Mechanism of tracheal stenosis may be due to EMT.At the same time,TGF- beta /Smad signaling pathway and transcription factor ZEB1,Snail1 may regulate the EMT.