Abstract:Objective: To investigate the effect of CDDO-Me on the hypoxia-induced activation of human pulmonary artery adventitia fibroblasts (PAAFs) and potential mechanism. Methods: Human PAAFs were cultured in vitro and randomly divided into four groups: the normoxia group (21% oxygen), the hypoxia group (1% oxygen), the hypoxia plus CDDO-Me group and the normoxia plus CDDO-Me group. Cell viability was determined by CCK8 assay. Transwell assay was carried out to assess cell migration. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) were detected to evaluate the level of oxidative stress. The levels of TGF-β1, TNFα and IL-1β were detected by ELISA assay. The expression of α-SMA and nuclear translocation of NF-κB (p65) were detected by immunofluorescence assay. The protein levels of α-SMA, collagen I, vimentin, phospho-Smad3 and Smad3, phospho-p65 and p65 were determined by Western blot. Results: CDDO-Me treatment (62.5, 125, 250, 500 nmol/L) decreased hypoxia-induced elevations of cell activity in a concentration dependent manner, which showed significant inhibition at concentration of 250 nmol/L and 500 nmol/L. CDDO-Me (500 nmol/L) remarkably inhibited hypoxia-induced migration and myofibroblast transformation of PAAFs, which reflected in improvement of hypertrophy, decrease in expressions of α-SMA, collagen I and vimentin. In addition, CDDO-Me (500 nmol/L) significantly inhibited hypoxia-induced increased levels of ROS and MDA, decreased levels of GSH and SOD, and improved the ability of antioxidation. Hypoxia increased the secretion of TGF-β1 and activate TGF-β1/Smad3 signaling pathway in PAAFs, which was attenuated by CDDO-Me (500 nmol/L). Besides, hypoxia-induced nuclear translocation of p65, phosphorylation of p65 protein, and the secretion of TNFα and IL-1β were inhibited by CDDO-Me treatment. Conclusion: CDDO-Me can inhibit hypoxia-induced PAAFs proliferation, migration, myofibroblast transformation and the secretion of inflammatory cytokines, which may be related to the improvement of antioxidation ability, and the inhibition of TGF-β1/Smad3 and NF-κB signaling pathway in PAAFs.