ABSTRACT
Objective The aim of this study was to explore the regulatory effects and mechanism of autophagy on epithelial-to-mesenchymal transition(EMT) in idiopathic pulmonary fibrosis(IPF). Methods The experiment was divided into two group: control group and experimental group(IPF group, autophagy induction group, autophagy inhibition group). A549 cells were cultivated by the conventional method in control group. The A549 cells of the experimental group were induced by TGF-β1(5 ng/mL). Then, no further treatment was given to IPF group. Rapamycin(10 μg/L) or 3-Methyladenine(10mmol/L) was given to autophagy induction group or autophagy inhibition group respectively. The hydroxyproline content of lung tissue was measured, and the mRNA and protein levels of α-SMA, LC3-Ⅱ or LC3-Ⅱ/LC3-Ⅰ, Beclin1, E-cadherin and Vimentin were tested by Realtime PCR and Western blot. Results At each time point, the hydroxyproline content of lung tissue and the mRNA and protein levels of α-SMA and Vimentin in the experimental group were significantly higher than those in the control group（all P<0.05）. The above detections in autophagy induction group or autophagy inhibition group were significantly lower or higher than those in the IPF group（all P<0.05）. The mRNA and protein levels of LC3-Ⅱor LC3-Ⅱ/LC3-Ⅰ, Beclin1 and E-cadherin in the experimental group were significantly lower than those in the control group（all P<0.05）. Moreover, the same detections in autophagy induction group or autophagy inhibition group were significantly higher or lower than those in the IPF group（all P<0.05）. Conclusion The autophagy and EMT played an important role in IPF. Induction of autophagy might inhibit the development of IPF by inhibiting EMT, and Inhibition of autophagy could promote the development of IPF by activating EMT.