Biofabrication. 2022 Oct 12.
Paraquat poisoning induces pulmonary fibrosis in vivo. The pathogenesis of pulmonary fibrosis is complex, which has prevented the development of specific treatments. Pulmonary fibrosis shows several characteristics including epithelial-mesenchymal transition (EMT), fibroblast activation, and extracellular matrix (ECM) deposition. To investigate pulmonary fibrosis, we designed a biomimetic multichannel micro-lung chip to imitate the in vivo interface between the lung epithelium and the lung interstitium. In our model, A549 lung epithelial cells and MRC-5 lung fibroblasts were used to test the efficacy of our chip-based model. Rat tail type I collagen and hyaluronic acid were used to simulate ECM and to provide a 3D microenvironment. The micro-lung chips were cultured with paraquat (0, 75, 150, 300, and 400 µM). The viability of A549 and MRC-5 cells significantly decreased with increasing paraquat concentrations. There were significant changes in surfactant proteins C (SP-C), alpha smooth muscle actin protein (α-SMA), and vimentin protein levels during paraquat-induced pulmonary fibrosis. SP-C levels were decreased in A549 cells, while those of α-SMA and vimentin were increased in A549 cells and MRC-5 cells treated with paraquat in the micro-lung chip. We also designed a reference model without interaction between the lung epithelial cells and fibroblasts. Compared to the non-contact model, co-culturing A549 and MRC-5 cells in chips induced more severe EMT in A549 cells after treatment with 75 µM paraquat and together defended against paraquat-induced damage. Thus, our novel co-culture micro-lung chip that models the lung epithelium and interstitium may provide a new approach for studying lung fibrosis and will facilitate drug development.
Keywords: epithelial-mesenchymal transition; micro-lung chip; paraquat; pulmonary fibrosis